From a copper engraving of a plague doctor in Rome, circa 1656

Across Europe between the the 14th and 17th centuries, a number of ‘Plague doctors’ donned protective suits like this to walk among dead and dying plague victims. Unsure of what might be causing these plagues, these suits were armor against a hazardous environment and are quite reminiscent of modern day hazmat suits. The image above depicts a late example from the city of Rome, complete with heavy cloak, leather gloves, glass goggles and conical birdlike beak covering the mouth and nose.  The impression of a carrion eating, scavenging crow or raven is almost impossible to miss.  Perhaps this engraving was intended as an early macabre from of editorial cartoon.  The significance of the conical or pointed beak is that various herbs and powders were stuffed into its end, in hopes of filtering out any lurking invisible plague vapors that might be inhaled.

Today, centuries later, some carnival costume mask may remind us of those heinous plagues. During the “Black Death” as much as half of Europe died in the span of four years.  There were many large epidemics  in history that are somewhat erroneously called “plagues” since these were probably not caused by the infectious pasteurella pestis bacillus. From antiquity to present the number of proper plague outbreaks caused by this bacillus though, might still number well over one hundred.  Between the 14th and 17th centuries the plague quit, then returned about 15-20 years later (almost with every generation).  The European rat population (where the bacillus is apparently not endemic) was repeatedly wiped out and took time to recover as well.

It is generally accepted however that there were three ‘great waves’ of plague pandemic in world history. The first noticeable “great” plague is called the “Plague of Justinian”. It occurred in 541 AD and was centered in the Eastern Mediterranean / Byzantine Empire area. As many as 5,000 people a day died in the streets of ancient Constantinople (by far the largest city in Europe at the time – named Istanbul today). In a year’s time this bout of plague killed perhaps 25 million people including the emperor Justinian himself.

The next and biggest great die-off is known as the “Black Death” which began in 1346 and lasted for seven years. This plague decimated perhaps 75 million people or approximately 1/6th of the world’s population. It is thought to have made its way from China or Central Asia (where the bacillus is indigenous in local rodents) along the Silk Road by caravan to the Mediterranean Ocean where ships carrying other rats or mice – further disseminated bacillus carrying fleas to ports throughout Europe and North Africa.   Europe especially, was remodeled by the Black Death.

The less disruptive, less specific “Third Pandemic” as it is called, lasted for more than a century (between 1855 and 1959) and was responsible for at least 12 million dead in China and India.  During this period the pneumonic form the plague ran rampant in Mongolia. All of the major epidemics of plague are thought to have originally blossomed outward from Central Asia.   Right now the pasteurella pestis bacillus can be readily found on any day, in the dirt or among rodent colonies living on the Asian, African, North or South American continents.  There is an ongoing occurrence of bubonic plague today, in Madagascar which broke out in 2014 and hasn’t yet faded away.

In humans the acute infectious disease caused by the bacillus Pasteurella pestis occurs in three forms: bubonic, pneumonic & septicemic.  The most common form bubonic, is characterized by buboes (bumps or blisters / inflammatory swelling of a lymphatic gland, especially in the groin or armpit).  Pneumonic plague  infects the lungs instead of lymph nodes.  Less common than the bubonic form but more deadly, the pneumonic form can be contracted by a flea byte or by airborne inhalation of the virus from an infected person.  Septicemic plague attacks the blood and causes blood clots but is rare.  Which ever form of plague is encountered, treatment with antibiotics has supplanted the treatment with sulfa drugs used in previous decades.  Early detection is still paramount for survival.

Segue to Vinegar

Vinaigre des 4 Voleurs / Four Thieves Vinegar

There is a story with various versions that dates back to one outbreak of plague in the city of Marseilles, France.  It seems that four incarcerated thieves (possibly caught for robbing the sick or dead) were pressed into labor.  They were forced to handle, transport and bury the corpses of plague victims.  Miraculously, the thieves continued to survive this punishment detail day after day while others about them were dying like flies.   Apparently the thieves routinely applied a concocted ointment they received from a local medicine woman.  Their survival was probably the result of certain herbs in the ointment acting as a repellent to the plague carrying fleas that transmitted the pestis bacillus.  The salve or ointment started with white wine vinegar as a foundation to dissolve and preserve the essence of these herbs.  In a version of the “Four Thieves Vinegar” believed to be authentic; angelic, horehound, meadowsweet, wild marjoram, campanula, camphor, cloves, rosemary, sage and wormwood were used. At least the last six herbs listed have aromatics that repel insects – like parasitic plague infested fleas.

The English word “vinegar” comes from the French phrase “vin aigre” – which means sour wine.   For as long as mankind has had alcohol to drink (about 9,000-10,000 years) he has had vinegar too.   The ancient Babylonians used vinegar as a condiment and Cleopatra used vinegar to win a bet.
Any plant sugars in solution can be fermented to create alcohol.  That alcohol (ethanol) can by deliberation or by neglect be exposed to open air and subsequently turned into vinegar by a different fermentation caused by acetic acid bacteria.

The “acetobacter” genius of the acetic acid bacteria (acetobacteraceae) family is the one most commonly used to make vinegar or to supply vinegar fermentation starter cultures (often called the “mother of vinegar”).   Products that are labeled vinegar usually contain a minimum of 4% acetic acid while the remainder is water, flavorings and trace chemicals.   Vinegar doesn’t spoil if sealed and has a practically indefinite shelf life.  It may oxidize, lose its aromatics or lose some water to evaporation if exposed to open air but it does that slowly .

Types of vinegar

The most common vinegars are cider, wine, malt, rice, balsamic and distilled. Today those have been joined by many flavored or seasoned variants. Vinegar can be produced from all sorts of things including coconuts, honey, beer, maple syrup, potatoes, beets, malt, grains, molasses, dates, sorghum, fruits, berries, melons and whey.

Wine vinegar is self explanatory.  It can occur in a few weeks or months after acetic acid bacteria in the atmosphere come into contact with wine. Aceobacter can spoil a soggy wooden wine barrel for example, if this is left too long unfilled and unused.   Malt vinegar which is popular with “fish and chips” is of course equivalent to spoiled beer.   Beer is usually fermented from barley and barley malt.   Scotch whisky can be made entirely of malted barley.   Malt is grain that has been germinated and has started to sprout.   The term “distilled vinegar” is a tad bit misleading because the vinegar itself is not distilled – but it is made from a concentrated source of ethanol. Authentic “Balsamic vinegar” is a very prestigious and expensive product that is first cooked and reduced from a white grape must, then fermented and then aged for a very long time in a succession of different aging barrels.


* “acid is second only to salt for elevating the flavors of your cooking. Just a few drops of acid in the form of citrus or vinegar can make a dish more complex — “brighter”

Vinegar is an important foodstuff and food preservative.  Vinegar can also be used to remove rust, prevent dandruff, soften stiff paintbrushes, kill warts, clean glass, clean tile grout and toilet bowls.   Like a vinaigrette salad dressing, a mixture of olive oil and vinegar make a fine furniture polish.   After the famous Holy Roman Emperor / King of Germany and Italy known as Frederick Barbarossa (1122-1190) drowned in the Saleph River (modern day southern Turkey) during the Third Crusade, his army collapsed.   His body was put into a wooden barrel and preserved with vinegar for the long trip back home.

Many sauces and food condiments like mayonnaise, tomato ketchup, spreadable mustard and pickle relish contain vinegar.  When Americans see a preserved cucumber they say “pickle” while in Ireland, Australia or the UK people might call the same item a “gherkin”.   A gherkin is actually a variety of cucumber and a cucumber is far from the only produce that can undergo the “pickling” process.   Beets, carrots, onions, tomatoes, cauliflower, cabbage, peaches, cherries and pears are frequently pickled as well.   There are several variations of the pickled cucumber or gherkin including: half or full sour, Polish style, sweet, dill, kosher, bread & butter and cornichons – those tiny little tart French pickles preserved with vinegar and spiced with tarragon.

Salt which was treasured in the ancient world, was used to preserve meats, eggs, vegetables and fruit because it drew moisture out of the foods and in so doing it inhibited the development of bacterial spoilage.   Produce can be preserved by a few different salt curing methods like dry salting, brining (strong salt solution), low salt fermentation and pickling.  Low salt fermentation and pickling with vinegar are similar processes in that lactic acid created in the first instance or acetic acid introduced by the second process, both lower the pH to a level that is hostile to bacteria. It takes a pH of about 4.6 or lower to kill most bacteria.  Clostridium botulinum is the tough, resilient and dangerous anaerobic bacteria that can flourish in stored foods that do not have high enough acid concentration or that were not heated hot enough or long enough when they were canned.

There are two traditional ways to go about pickling; the slow way by fermentation or the fast way with vinegar.  The fast way involves soaking some vegetable example in a salt bath overnight. This removes some water and better allows vinegar afterward to penetrate the vegetable’s tissues.   Alternatively, pickling lime (calcium hydroxide) is used instead of salt for this initial step.  Lime has the effect of making a vegetable like the cucumber crisper; it is there for the texturing effect alone and not for preservation.  The lime or salt solution is rinsed off after about 24 hours.  Vinegar, accompanied usually with antimicrobial pickling herbs and spices (like cinnamon, mustard seed, cloves & garlic) is then added.

German sauerkraut, Korean kimchi, sour and dill pickles are examples of the slower fermentation method of pickling which might require a couple of weeks to a couple of months.   Surrounding produce in brine solution deprives undesirable bacteria (most types) oxygen to grow but creates a favorable anaerobic environment for lactic acid bacteria.   Lactobacillus bacteria then ferment or convert natural sugars into lactic acid.

* A typical process for making sauerkraut using this slow pickling process is to place unwashed shredded cabbage into a sterilized stone crock.   Some outer leaves on the cabbages may be removed but wild yeast are to be otherwise retained.   Salt is repeatedly sprinkled between thin layers of shredded cabbage and packed firmly down.   Finally a dinner plate or something similar and additional weight (preferably in the form of a limestone rock) presses everything down; a sanitary cloth covers the crock.   In the process of waiting 4 to 6 weeks for nature to take its course: water is pulled by salt and pressed out by weight to form a brine solution.   Also a small amount of lime is dissolved from the rock which assists in the formation of lactic acid and provides the sauerkraut with extra flavor.

Products preserved by the two pickling processed mentioned above should be safe to eat for several months afterwards.   Cooking with heat and/or refrigeration will prolong their longevity as food.   High acidity should prohibit most bacterial growth but occasionally the acidity of vinegar (acetic acid) used or lactic acid fermented is not adequate.   To be considered safe for longer periods, even pickled foods need to be subjected to the ‘long time duration at elevated temperature’ of proper canning technique.

Making Vinegar

Just as with pickling there is a fast way and a slow way to make vinegar.  The fast way involves inoculating a liquor or fermented juice with a starter culture of bacteria called “mother of vinegar”.   “Mother” itself is a cellulose or complex carbohydrate that forms as surface slime on vinegar that is long exposed to air.  Acetobacter bacteria are aerobic which means they are oxygen loving or thrive in air.   In fast commercial vinegar production, a source liquid which already contains ethanol is started with this bacterial culture and extra air is added to oxygenate and promote the fastest fermentation.  The fast vinegar method may take only two or three days to complete.   Slow traditional methods for making vinegar on the other hand might require a few months – to a year to complete.  Here the acetic acid bacteria must be captured from the air before fermentation can even commence.  Here a potentially useful surface slime might build up that can be skimmed off and collected for use as mother elsewhere.

Homemade vinegar

Web pages can be found on the Internet which give step by step instructions for how to make vinegar from a bottle of wine for instance.  Usually these instructions call for the use of some Mother of Vinegar.   Little containers of this can be purchased online if need be, from places like  It is very easy however to make vinegar the old fashioned way.  The best results would probably be returned by starting with a jug of simple, unpasteurized sweet apple cider.  Taking the top off and letting the jug sit for a week or two will allow wild yeast to make the cider alcoholic.  Another few weeks of exposure to air will create apple cider vinegar.   Again, adding a little ‘Mother’ if it is available will help speed the process.  At some point after the homemade vinegar becomes strong enough, it should be bottled.  Vinegar should be stored in a narrow-neck bottle with a tight seal to prevent oxidation and loss of flavor.  New vinegar should be aged for at least several months, to clarify and allow the flavor to mellow.

* Vinegar eels are just barely visible and it would take about sixteen mature ones laid end to end to equal one inch in length.  These tiny nematodes () like to hang out and breed in vinegar.   They consume the bacterial and fungal microbes that form “Mother of Vinegar”.  These worms can inhabit many vinegar products that are left too long exposed to air, because their microscopic eggs often ride dust particles that float around in the air.   In the U.S., commercial vinegar is filtered or pasteurized to eliminate these little creatures, but they are not toxic or parasitic.  Like the brine shrimp that are larger, vinegar eels are actively cultivated and used as food for young aquarium fish fry (baby fish).   A hobbyist might grow a culture of eels from apple cider/vinegar because their eggs come with the apples naturally.

*To make juice, apple fruit must first be macerated and squeezed through a press.  Filtered this becomes apple juice, unfiltered this becomes soft or sweet apple cider.  Fermented the juice becomes alcoholic – hard apple cider.  If frozen, ice can be pulled out leaving less water so this more concentrated form of hard apple cider becomes “applejack”.   The same process can be accomplished with a bottle of wine or beer but some of the liquid must be removed beforehand to prevent ice from bursting the bottle when it expands.  Of course this process would be illegal almost everywhere booze is normally sold because it is considered to be distillation (freeze distillation).  You don’t want to deprive your government of one of its most lucrative tax bases.

*The drip still can be made from pots and pans from about the kitchen. Euell Gibbons published images of the concept more than fifty years ago. A simple apparatus like this is appropriate for collecting the oils and fragrances of herbs. Just toss a handful of rose pedals or other herb into the water of the bottom pot.  Apply heat and droplets of vapor will condensate and drip into the cup.



Considering Leather

The most utilitarian and multipurpose material ever readily available to early man came from the hide of an animal.  Making leather from hides or furs from skins might have been the first human industry.  Until the very recent dawn of plastics and synthetic fibers, leather and fur were nearly indispensable commodities.  Leather is a superior material for several applications like footwear, saddles and upholstery and still remains the material of choice over any synthetic alternative.  However, turning a smelly raw animal skin into usable leather is a difficult process.  Before certain procedural and chemical advancements in the previous century, commercial tanning was even yet a more laborious and time consuming pursuit. This post will endeavor to briefly separate and identify some of the varied techniques used in leather tanning, while perhaps empowering some readers with a few ‘do it yourself’ type leather tanning skills.

What is leather?

A mammal’s skin or hide consist of a thick center layer called the “dermis” or “corium” which is sandwiched between a thinner epidermis on the outside and a subcutaneous fatty layer on the inside.  The corium of a fresh hide contains between 60-70 percent water and 30-35 percent protein by weight.  Of that protein about 85 percent is of a special fibrous type called “collagen”.  These protein fibers are held together by chemical bonds.  Tanning chemicals (tannins, enzymes, acids, bases or salts) in effect alter these bonds between collagen fibers, remove water and dissolve natural fats within a hide.

If a fresh hide can be frozen, salted or quickly dried then it can be temporarily spared an otherwise inevitable decomposition from bacterial rot.  A fresh hide may have a few useful applications in raw form though, considering its tendency to shrink substantially upon drying.  However should dry rawhide be re-hydrated, it immediately becomes susceptible again to rot.  Raw hides have value and those destined for leather processing are soaked in brine or packed in salt at the slaughterhouse before being shipped to a tannery.  Should they desire, tanneries could preserve surplus hides for over a year by packing them in more salt.  Tanning is both a physical and chemical process that preserves a hide and converts it into leather.  The removal of membranes and subcutaneous fat from the underside and the optional hair removal on the topside entail just one or two physical processes.  The chemical processes reorganize some organic molecules, while often coating or replacing others with outright inorganic substitutes.

The leather industry has an odorous history and one accompanied by pollution. Today there are three distinctive methods to use for tanning a hide: by the ancient vegetable process, modern chromium process or novel aldehyde process.

Tanning liquors

Historically either alkali or acidic solutions have been used in tanning.  A Native American Indian might have soaked a deer hide in a potash solution for example.  Also called “lye”, this caustic alkali or base solution of potassium carbonate can be created simply by leaching water through wood ashes.  Lye (potash/potassium carbonate, sodium hydroxide/caustic soda & potassium hydroxide) or other alkali solutions like hydrated lime will remove the hair from hides.  Both sodium sulphide and sodium hydrosulphide will dissolve hair.   Even some weaker alkaline solutions like ammonia collected from human urine; have the effect swelling the hide, enlarging follicles and loosening hair at the root.

* Several centuries ago in urban areas like 16th century London, it was common practice for poor children to collect urine from private “chamber pots” and public “piss pots” to sell it for money.  Urine is a rich source of urea and decomposes into ammonia, which was an important source of nitrogen to factories that could not yet synthesize such a chemical independently.  At least three important industries required urine back then.  Textile manufacturers used ammonia for altering the color of vegetable dyes and adjusting pH in dye baths, gunpowder makers needed the nitrogen found in urine to make critical potassium nitrate and tanners also needed or favored urine to produce leather. 

* Even back in ancient Rome, urine pots were placed in the streets for the public to fill at leisure.  These pots were collected and used to wash laundry.  The laundry came out bright and clean and the practice was so popular that Emperor Vespasian taxed this urine in the 1st century AD.

* Today household ammonia (5 – 10% pure ammonium hydroxide) is still critically acclaimed for its general cleansing ability, including for laundry.  Just don’t mix ammonia with bleach (calcium hypochlorite) because that will create dangerous fumes.   

Two mildly acidic and astringent chemicals used to produce leather are alum and tannin.   Alum (or specifically hydrated potassium aluminum sulfate) is used as a blood coagulant in articles like styptic pencils, in underarm deodorants, as a dye-fixer or mordant for wool and plant fibers and in tanning solutions where the hair or fur might want to be retained.  Alum creates a less toxic alternative tanning liquor and for small jobs is being used more frequently now than it ever was in the past.  Tannin is easier to find as it occurs naturally in the bark and leaves of several different plants. This astringent polyphenol binds to and coats collagen proteins, making them less water soluble and less vulnerable to bacterial decomposition.  Tannin is but one type of polyphenol out of thousands, and these phytochemicals give vegetables and fruit both their color and beneficial antioxidant properties.

* Astringents taste bitter to the tongue, pucker up the mouth and tend to shrink or constrict body tissues in general. An astringent tanning liquor then can be expected to tighten its hold upon hair, as opposed to a lye liquor that would swell and loosen its hold. 

* Tannin from tree bark is far more traditional than tanning liquor from alum. By the early 17th century Industrial Revolution, large plots of the northern English countryside were being ravaged to mine alum rich shale deposits, which were then baked in bonfires using all the firewood from the surrounding landscape.  Probably more of that alum found its way into textiles than leather but by this time England was running out of trees too. 

In the past the commercial treatment of leather with tannin required massive amounts of tree bark (approximately an equivalent weight of bark to the weight of a skin).  In America, after the forest near early Boston and New York City were denuded, tannin harvesters ascended to the Catskill, Adirondack and Allegheny mountains to placate their ravenous need for tannin. Whole hemlock forests were flattened of trees, merely for the tannin in tree bark while the softwood was largely abandoned. The practicality of building tanneries closer to the source of tannin and then shipping hides long distance rather than tree bark was eventually realized.  Leather tanneries often formed the central economic hub of many new communities in American outward expansion.

The word “tannin” is derived from a German word meaning oak.  Several different plant species (including chestnut, eucalyptus, mangrove, maple, sumac, wattle, and willow trees or bushes) are high in astringent tannin and are commonly used in vegetable tanning liquors.  It would be possible to leach a tannin rich tea from the dead leaves of most any deciduous tree in the autumn.  Some people have boiled bran (the husk of wheat or rye kernels) to obtain tannin.   Hemlock tends to make leather reddish-brown while oak produces yellowish-brown and chestnut while famous for making thick Italian shoe-sole leather, turns collagen fibers dark brown.  Before introduction of chrome tanning solutions in 1858, most all leather produced was simply “vegetable tanned” leather.

Keith Weller acquired from USDA ARS (Website)

Keith Weller acquired from USDA ARS

So around the same time that the trans-American railroads were being constructed, Texas cowboys were driving cattle herds up to meet the railhead and jobless Civil War veterans were harvesting wild buffalo for meat; new chromium leather tanning techniques were suddenly gaining favor in Europe.  The new rails were soon used to ship cattle back east (notably to Chicago) and products like buffalo hides back further east to established tanneries perhaps in Boston or New York City.  The fact was that those eastern American tanneries relied upon much human labor and slow vegetable tanning chemistry.  Typically a cow hide might need to soak in a barrel of tannin liquor for six months to produce high quality leather.  Although not especially desired or in demand by American tanneries, a few bundles of Buffalo hides made their way to England; where they were enthusiastically received and thousands more were immediately ordered.  The decimation of the great American Bison herds is directly traceable to bovine diseases spread from domestic cattle and the commercial slaughter demanded by global economics.  In a twelve year period beginning in 1871, about six million buffalo hides from approximately nine million animals slaughtered – were shipped to Europe.


Somewhere back in the middle of the 19th century, the effects of Chromium (III) upon a rawhide were discovered.  These solutions came from dissolving elemental chromium in sulfuric or hydrochloric acid. Two solutions, chrome alum (or chromium (III) potassium sulfate) and chromium (III) sulfate are noteworthy in tanning.  The latter of the two solutions is the simpler, cheaper form preferred today by the commercial tanning industry.  Not nearly as toxic as the hexavalent chromium (IV) variety of chrome used on shiny automobile parts, chromium (III) tanning liquors nonetheless contain heavy metals and should be disposed of carefully.  In the right pH environment chromium (III) can oxidize into undesirable and environmentally persistent chromium (IV).   Chromic acid which is different but related, is noteworthy for being a strong and corrosive, oxidizing agent that will attempt to consume organic compounds.

About 85 percent of all leather today is chrome tanned.  ‘Chrome tanned leather’ is thinner, more eaten away and more flexible than ‘vegetable tanned’ leather.  Chrome tanned leather is good enough though for most situations and may even be the preferred choice in a few applications; given its flexibility and better resistance to shrinkage caused by water.  Some chromium remains behind in the hide after tanning, as it is tightly bound to the collagen proteins.  The reason that chromium has become so ubiquitous in today’s tanning industry is because it allows great reductions in both time and labor.   Vegetable tanned leather which is more expensive, is usually reserved for quality items like belts, purses, wallets, shoe soles, horse bridles, harnesses and saddles.

Both vegetable but especially chrome tanned hides are tumbled and pounded around in rotating drums like the museum piece imaged above.  Once the desired level of chrome penetration into the hide is achieved (which takes about 24 hours) the hides will come out “wet blue”; not the tan color shown.  Several varied finishing techniques would follow next.

Whereas vegetable tanning might require grueling labor for fleshing and stretching the hide and long months of exposure to tannins inside a vat, chromium tanning creates a product in just days or weeks.  The substantial chore of fleshing is much simplified by virtue of these chemicals dissolving most of those unwanted fatty tissues. The details of temperature, pH and other chemical factors are more complicated, critical and caustic with chrome than with vegetable tanning liquors.  In this present day and age, one can no longer just buy U.S.P. approved chromium potassium sulfate crystals from the local drugstore either.  Chrome tanning on an individual basis is not practical, but vegetable tanning is.

Aldehyde Tannage 

While chromium (III) solutions leave tumbled hides a color that is referred to as “wet blue” a newfangled process leave the hides “wet white”.  The first and most notable, quick working base chemical used in “chromium-free” aldehyde-tanning was the water soluble gas, formaldehyde.   Not creating the pollution that chrome does, some small amount of toxic formaldehyde residues nonetheless remain within the clothes, shoes and car seats made with this leather.  A newer chemical called glutaradehyde is highly reactive towards proteins, but leaves aldehyde wet white leather comparatively ‘baby safe’ and allergen free.  Glutaraldehyde is more expensive than formaldehyde, it sterilizes or inactivates viruses and bacteria, it is used to remove skin warts and is occasionally used in hydraulic “fracking” fluids to unclog oil wells of microorganism buildup.

The American Indians and probably many other nomadic aborigines as well typically used the brains of an animal during the hide tanning process.   Boiling the brains with a bit water creates an oily soup that can either be used as a solution to completely submerge and soak a hairless hide or be rubbed into the underside of a fur.  Once the treated skin is smoked over a fire however, chemical changes occur and a mild aldehyde type tannage takes place. Almost any organic oil benefits the flexibility and durability of leather.  Some famous leather ointments like Neatsfoot oil however will darken leather while brain oil is less likely to.

*Neatsfoot oil (a brand name) actually comes from the tibia (lower leg –shin bone) of a cow; it doesn’t easily freeze and absorbs readily into leather.  Sulfating the Neatsfoot oil allows it to penetrate even further. 

Price of rawhide

The U.S.A. is only the eighth largest producer of leather in the world, with a total 669 million square feet produced in 2011.  The other top ranking leather producers superseding the U.S. that year were: China (3,913 M sq. ft), Brazil (1,832 M sq. ft.), Italy (1,573 M sq. ft.), Russia (1,460 M sq. ft.), India (1,397 M sq. ft.), South Korea (1,083 M sq. ft.) and Argentina with 715 million square feet of leather produced.

In the 1990’s the price of a wet nondescript cowhide in the U.S.A. was approaching $1.00 per square foot. Today’s price for a wet steer hide (over 53lbs.) from a slaughterhouse is about $70.00.  Because of its potential as leather, raw cowhide is generally more valuable than pig, sheep or goat hide.  However if the hair is to be retained then hair quality or unusual coloration like Angora goat or Holstein cow can fetch much higher prices.  There are authorities on this subject.

The price of meat influences the price of leather.  Tanneries must compete with food companies to get the hides because what is not converted to leather is immediately converted to gelatin instead.  Gelatin is made by boiling the collagen from skins, tendons, ligaments and bones in water.  Europe produces a large share of the world’s gelatin, supplying about 400,000 tonnes per year.  More pig skin is converted to gelatin than is cow, sheep or goat skin.  Gelatin itself is used in puddings, candies, marshmallows, ice creams, cakes, shampoos and miscellaneous cosmetics.

Removing the hide

 Flaying or “skinning” the hide usually takes one or more very sharp and slender knives.  These knifes generally dull quickly while skinning and need to be re-sharpened periodically.  The thickest skin on an animal is usually around the neck and shoulders.  The thinnest skin, which is more vulnerable to nicks by a skinning knife, is at the belly.   When removing the skin in one piece the starting incision is usually made from the chin, down through the center line of the belly, to the rectum.  From each foot, cuts running down the inside of the legs come down to meet the centerline.

Small the animals have thinner skins than large animals.  The most difficult skinning would have been preformed by a fur trapper that was compelled by market demands to tediously flay around the head, face and feet, or by a taxidermist who’s flaying gets even more intricate.  Furriers and taxidermist are rare these days but their profession still requires much more skill, patience and attention to the details of skinning than an average hunter would employ.

There is more than one way to skin a cat

Large industrialized slaughterhouses can remove a full grown steer’s hide in less than a minute.  Techniques differ but these factories usually employ moving assembly line division of labor or small teams working simultaneously on one carcass.  Skinners might use  pneumatic “roller skinners” or normal knives and a mechanized skin pulling apparatus.

factory skinner using a flaying knife

team using a hide puller

For small furs like rabbit and mink a commercial furrier might purchase or construct a hide pulling machine that quickly shucks the skin, leaving it inside out.  The only labor involved is making a few precise cuts beforehand, around the head and feet.

DIY Vegetable Leather Tanning

There are many, many books, pamphlets, magazine articles and YouTube videos detailing “do-it-yourself” tanning techniques.  The novice should focus on the overall intent of tanning and less upon one particular technique.  The intent is always to remove the natural water and fatty tissues from a skin and replace them with something else.  A novice should initially avoid tanning large hides and seek something smaller. The amount of labor required for a large hide (bigger than a deer or sheep) can quickly become discouraging or overwhelming for the un-initiated.  The first decision to be made is whether or not the hair should be removed.

Caustic lye, potash or lime would be normal choices for de-hairing solutions.  It is possible however to simply submerge and tie a deer hide perhaps in a cold mountain stream and leave it there for a week or two. Returning later one will find that the hair pulls out easily by hand, no caustic solution was needed.  Many sources are adamant that the first thing to do with a hide is to scrape the flesh from the underside.  Alternatively though other tanners might prefer soak a hide first, thereby loosening both hair from one side of the hide and softening those fatty flesh tissues from the other.  If the tanner of furrier decides to keep the hair then he skips the de-haring alkali bath and moves on to fleshing.

* Buffalo hunters in the past didn’t flesh their hides at all, but cured and preserved the hides for shipment by spreading on salt and drying them out in the sun.

The “Indians” native to North America were expert leather tanners.  Every bit of their clothing was made of leather and often their homes were as well.  For scraping the hide they used tools made of bone, rock, wood or antler.

Factories involved in vegetable tanning were also compelled to physically flesh the hide and they historically favored a fleshing knife and a beam.  The fleshing knife is simply a rather dull, flat strip of metal with two handles.  The beam was usually a short log angled from the workers waist, to the floor.  This provided a work surface that allowed the wet and heavy hide to be moved around easily, and provided a mechanical advantage by allowing the tanner to lean into the work with his weight.


Once properly fleshed, either a de-haired hide or a fur with all its hair intact will undergo essentially the same processes afterwards.  While tannin will stain things brown it may be desirable for de-haired hides but an alum solution might be chosen for hairy furs.  Small animal furs might need to soak in a tanning liquor for just a few days whereas large hides might need to soak for weeks.   The judgment call of whether a hide has set in a particular tanning liquor long enough or not, is made by cutting through a small piece of hide and examining it in cross section.  If the sample cross section is the same consistent color throughout then this part of the procedure is finished.  The hide is now tanned from a chemical perspective but much physical labor remains.  Any pinkish-ness or fluctuation in color from the edge to the center is an indication to soak the skin some more.

At this point, should the treated wet hide or fur be simply tossed out upon the ground to dry, it would shrink, curl and stiffen into a very unusable product.  To get the strong but flexible leather we are familiar with that hide needs to be washed, rinsed, twisted or rung out like a towel and then thoroughly tortured as it dries.  A half dried skin can be laid over a tree stump and using a soft mallet, pounded over every square inch of its surface with short glancing blows .  At some point before all the moisture is gone, the leather is oiled.  It is this tedious but important, continual stretching, pounding and working of the skin as it dries, that produces flexible leather.

   Un-tanned rawhide can be preserved by drying it out.  If it is not to be tasked with some immediate purpose like being stretched over a hollowed out log to make a drum, then it can be saved for proper tanning at a later date.  Some rawhide might exist in a transition state, being only partially tanned.  Stretching a hide on a frame, or tacking one to a barn wall are popular methods of drying skins out.  Residual bits of fat or flesh can be scraped at leisure, either the suede or epidermis side can be attended to and once it’s flat & stiff the dried rawhide can be stored inside.

The novice or independent furrier has many options to improve his fur.   Furs can be washed in dish-washing detergent to remove oils and odor.  Vinegar and salt solution can be used to “pickle” the skin which helps “set” or lock in the hair.  The pickling solution is usually neutralized with baking soda before the fur hits the alum bath.  Once dry after the tanning bath, a fur might be rinsed in gasoline or naphtha (white gas used in camp stoves and lanterns) to remove any lingering oils or odor.  [Dry cleaners predominately used naphtha or another flammable petroleum fraction before 1911].  The flesh side of the fur might be sanded with sandpaper to remove high spots, making the suede uniform and level.  When finishing a fur it might be brightened by tumbling it in cornmeal, bran or sawdust which is then combed or brushed away.

Individual tanners working with a hairless hide might consider smoking it over a fire.  Some American Indian tribes once made the majority of their clothing from smoked deer hides.  After being fleshed, de-haired, cured in a bath of boiled tree bark tannin, worked to pliability and bathed in fat or brain oils, a deer hide was commonly draped over fire.  Being supported by a little tent like frame of green tree boughs the hide was rotated occasionally, collecting preservative chemicals and additional color along the way.

Once again, there are many sources and even videos of this topic available in the library or on the Internet.  Some of these sources have excellent information others do not.  The reader should be aware of several alternative vegetable tanning methods or recipes before religiously adhering to just one.

Other leather

   There are some schools that teach tanning and/or taxidermy and colleges or universities that offer chrome and aldehyde tanning curriculum.  There are products that disguise the origin of leather and some new organic products for vegans that imitate leather.  Often commercial leather is split, yielding at the least two different products; a “top grain” and one or more layers referred to as “split hide”.

Patent leather has a shiny, glossy finish and gets its name from a finishing and polishing process that was patented some two hundred years ago.  A satisfactory substitution or duplication of that process can be created by painting leather with layers of pigmented linseed oil (similar to oil painting on a sheet of canvas) and then with layers of varnish or lacquer.  Modern patent leathers (not vinyl or poromeric imitation leathers) usually have plastic coatings.

An “aniline dyed” leather refers to a very high quality ‘top grain’ leather that has been dyed clear through with a soluble dye.  A hide’s entire natural surface with pores and imperfections is visible with aniline dyed leather. No sealer, paint or insoluble dyes were used.  Should imperfections like scratches, blemishes or scars be sanded or disguised then the improved leather is referred to as “semi-aniline” dyed.  Most leather car upholstery is “pigmented” leather, meaning“semi-aniline” dyed leather with a heavy durable, protective, pigmented polymer surface coating.   Aniline is also a precursor used in the manufacture of polyurethane.

The Chinese were known to have boiled leather to make armor.  Probably many cultures over the centuries used leather armor but few if any examples exist in the historical record because they would simply biodegrade.   There might have been a lot of boiled leather armor back in medieval times but no one knows for sure now.  Boiling leather makes it shrink, thicken and harden.  Boiled in water or perhaps oil or tallow, the leather becomes mold-able for a short time and will freeze or set into shape as it dries. Overcooking makes it brittle and likely to shatter.  This site discusses making leather armor.

Authentic cheetah, giraffe, tiger and zebra hides are rare now but they were once fairly common.  Some leather producing outfits have taken to printing the hair of cow hides with ink, in patterns resembling these animals.   Even the hides of Holstein cows might be suspect.

As long as people continue to eat meat, there will be a continual supply of animal skins.  The rate of human population expansion is unsustainable and as a species we are soon to eat ourselves off this planet.  Nonetheless some vegans and or members of PETA (People for the Ethical Treatment of Animals) would have us believe that many animals are raised and slaughtered solely for the leather.  Aiming squarely for this demographic, companies like MuSkin, Myx and Mycoworks are actually growing, convincing leather substitutes by using mushrooms.   A substrate, matrix or mat of linen or hemp fibers actually gives this artificial leather its integrity and strength.  In essence either the chitin from the cap or the mushroom mycelium itself fills the spaces between mat fibers.   Apparently incubation and manipulation of fungus while growing can be controlled to a point where zippers can be incorporated without sewing.   Apparently members from the gilled Pleurotus genus and the non gilled Phellinus genus of woody mushrooms are producing the best mushroom leather  <images> or <other images>  results.

MISC informative LINKS

Some chemicals used in leather processing


Hemlock history in New York

Buffalo destruction / global market

Ethnobotany of tannins

Leather furniture facts

World Statistical Compendium for raw hides and skins, leather and leather footwear 1993-2012   <PDF>



Curing & Preserving meat



Although potentially a messy and inconvenient chore, the ability to procure one’s own food by slaughtering an animal is an essential skill for the well rounded and self sufficient individual.   This post offers some brief suggestions on how to butcher and process meat properly.  If fresh meat is not to be cooked and consumed immediately, there are some time honored meat preservation methods to choose from.  Jerking (drying), canning or salt curing & smoking methods easily come to mind.  Freezing may have become the most convenient way to preserve meats since WWII but these will still begin to deteriorate in other ways if they are left in a freezer too long.  Frozen meats are also dependent upon continuous uninterrupted sources of electricity.

Processing, curing and preservation methods may differ between animal species.  Raw fish for example, which begins to deteriorate very quickly can still be canned, smoked or turned to jerky.   The precautions for fish preservation differ by being more urgent.  Traditionally larger animals were butchered only when the climatic temperature dropped to levels that retarded meat deterioration.   It is no mystery why today’s deer, elk or moose hunting seasons begin in the fall.  When butchering large to medium animals like cattle, deer, sheep, goats or pigs, the first significant priority is to reduce the carcass’s internal heat.  The best way to do that is to bleed it, remove the skin and split the carcass.   There are probably as many detrimental fungi and bacteria lurking inside the meat as there are outside it.  The quick reduction of internal body heat in a carcass is the first step in reducing undesirable microbial or enzymatic deterioration of meat.  Snow banks and cold concrete floors can act as desirable surfaces in this heat reduction endeavor.

pre - 1911 "Reefer car" / Wikimedia commons

pre – 1911 “Reefer car” / Wikimedia commons


 In modern industrialized nations, refrigeration has changed our diet and has permitted the manifestation of the modern supermarket.  In urban areas, before refrigeration came along, fresh meat could be immediately consumed by a large populace, before it had a chance to spoil.  Before refrigeration and outside urban areas, meat harvesting was traditionally preformed in the fall or winter.  Cold temperatures assist in processing and preserving meat by discouraging bacterial activity both inside and out.  A century ago the availability (or not) of fresh meat and vegetables was dictated by seasonal and climatic temperature.   Initially commercial meat processors and brewers relied upon refrigeration from wintertime ice blocks cut from lakes and stored in sheds.  Properly ice ventilated “refers” or refrigerated railroad boxcars began shipping meat, dairy, vegetables and beer around the U.S. in the 1880’s.

US National Archives image /1917-18

US National Archives image /1917-18

Although invented a few decades before on both sides of the Atlantic Ocean, artificial refrigeration did not find successful application in the meat packing industry until the turn of the century and its accompanying delivery of commercial electrical power.  By 1914 artificial refrigeration was the norm for perishable food wholesalers and retailers.  Like milk or newspapers arriving on the doorstep, ice blocks were delivered to the ‘iceboxes’ of most urban homes.   In the 1930s, newfangled electrically powered household refrigerators appeared, but since coinciding with the ‘Great Depression’  – only the affluent could afford them.  Rural areas would wait much longer for delivery of electrical power.   After WWII, household refrigerators finally became common for the rest of the nation.

No longer restricted by the seasons, today we can buy fruits or vegetables “out of season” because they are maintained in a chilled state while being shipped from far away.  Likewise, supermarkets and groceries presently offer us plentiful supplies of fresh cut meats; due to the marvels of electricity, artificial refrigeration, and oil dependent transportation supply chains.


 Curing– can be a vague term because it is a process where so many ingredients or methods used can apply.  The only essential ingredient in a cure is salt (plain NaCl / without iodine).  Salt draws moisture out of the meat and it shuts down most microbial activity.   Although humans like other animals require salt in their diet, and at moderate levels it may enhance taste; salt has actually been such a historically valuable trade commodity because of its capacity to preserve meat.  “Corning” is the process of treating raw meat to dry salt crystals (any type of salt:  pickling, rock, kosher, dairy or canning – but not iodized which may cause discoloration).  There are quick acting “dry” cures where salt crystals and perhaps additional dry spices are packed directly around the meat.  “Wet” cures are essentially brine solutions in which meat is submerged and soaked.  In either case salt causes water to be drawn out of both muscle tissue and out of undesirable microbes by osmosis.  “Pickling” meat generally refers to using a curing mix or solution that also contains sugar and extra spices.  Sugar or honey might be included in a cure to counteract the harshness of excessive salt and to keep meat moist and tender.  Some spice combinations don’t work – garlic and black pepper can overpower a cure.   A “hard cure” implies a process involving both salt curing and long term exposure to preserving pyroligneous acid from creosote in wood smoke.   A hard cured ham or slab of bacon can become very dehydrated over time.  “Ageing” is a term usually reserved for beef.  Quality, tender “premium” beef is sometimes “dry aged” and is usually only to be encountered in a good restaurant.  The general public can only purchase a compromised product from the grocery, referred to as “wet aged” beef.

   Jerky” is an Anglicized version of a previously Spainglacized (?) version of a original Incan word: “ch’arki” – meaning dried meat.  Although any meat can be “jerked”, venison and lean beef respond best to the process.   Obviously low air humidity is necessary for the process.  For simplicities sake the raw meat can be dressed into the form of large and wide, but thin slabs before being introduced to the cure.  Either a dry salt cure or wet brine solution should be applied to the meat.  Afterwards the individual slabs are cut into thin strips and spread on a rack.  Whither exposed to sunshine or spread on racks inside, the meat should dry enough eventually, to snap rather than fold when it is bent.   A dry cure might produce results more immediately, because a brine-cured meat might soak in solution for a 3-6 day period before being removed for drying.  Below is an example brine recipe that might as easily be applied to a ham as it is to jerky.



Naturally, meat can be canned at home.  This post won’t delve very far into the details of canning but the main thing to remember is that any improperly canned foods are subject to developing botulism.  Clostridium botulinum is a curious, heat resistant bacterium that despises oxygen.   So while a host of bacteria like salmonella, E.coli, and listeria monocytogenes are killed at boiling water temperatures (100 deg C / 212 deg F),  botulinum spores locked within an airtight can, bottle or glass jar – would not be killed.   To insure canned food is safe, home canners must maintain an elevated temperature for an extended time.  By using a large specialized pressure cooker known as a “pressure canner”, the cook is able to reach an abnormal 115.5 deg C / (240 deg F) temperature by essentially doubling the atmospheric pressure first.   To be safe, that high temperature is maintained an hour to an hour and a half.


The Carib Indians were smoking fish over fires to drive flies from drying fish jerky when Christopher Columbus discovered these “Indians” in the New World.  Almost every type of fish responds well to curing and smoking but fish with a high percentage of oil (greater than 5%) do not air dry well.  Oily or fatty fish that do not dry properly are often preserved by “corning” instead.  Three to four generations ago many people in coastal regions continued to salt pack fish away in wooden barrels in the same way others inland might have stored “pork butts” or bacon away in barrels.   Requiring no refrigeration, freshly cleaned and dressed fish were sprinkled with corning salt and then stacked in a keg.   After about four days the salt pulls enough moisture from the fish to create its own brine solution.   Then the fish are rotated and re-stacked in the barrel, more salt and fresh water are added until the brine solution covers all the fish.  The fish should be firm when the salt has completely penetrated through the flesh.  Before consumption, the excess salt is washed and rinsed away, and fish are soaked and refrigerated in fresh water overnight.

* In the Great Lakes region people have occasionally contracted ‘broad fish tapeworm’ – from eating uncooked pickled pike, walleye or other predatory type lake fish.  Freezing the fish before pickling eliminates this threat (as does cooking).

Fermented Fish

Several cultures have resorted to fermentation as a method of fish meat preservation.   In the Mediterranean, anchovies are allowed to ripen for at least one half of a year before they are considered ready.   Orientals might ferment anchovies, shellfish, squid or shrimp for more than a year to create that dark brown “fish sauce” they cook with.  Scandinavians might eat “Hákarl”, “Surströmming” or “Rakfisk” which are so odorous as to send normal people into flight.  Eskimos not only ferment fish but might toss birds, sea lions, walrus, whale parts or anything else with protein into the same earth covered fermentation pit.   Fish fermentation works because most bacterial activity is halted as the level of acidity increases.


The same preserving techniques used for other meats can also be used on fowl.   Since fowl seems to dry rather quickly, brine curing solutions are preferred to dry ones.   Turkeys and chickens are seldom hard cured (smoked) whereas ducks and geese can be because of their higher fat content.


Driving out excess moisture from meat deprives bacteria and fungus a furtive environment to grow.  While salt cured pork hams and bacons may hang for years in a smokehouse, the primary purpose of a salt cure and of smoke is to dehydrate and preserve.  Only cheaper cuts of beef from the chuck, rump or brisket are improved by salt cure and smoke preservation.   Cures for beef will still employ salt, but are also sweetened usually with something like brown sugar, maple syrup, molasses or honey.

Pastrami, corned beef and ‘bully beef’ are salt cured and packaged or canned without being smoked.  Beef being a larger animal, has about twice the number of basic or primal cuts as does pork.  There is little agreement or standardization between cultures or countries on how a beef should be cut.  Thanks to refrigeration, beef can be deliberately aged to improve its character, but pork is seldom treated more than a couple of days this fashion.

Unless you go to some effort, the only way an individual is likely to encounter aged beef is to order it in a good restaurant.  The public has no access to properly aged beef in a grocery or supermarket.  Today meatpackers just inject the beef riding conveyor belts, with chemicals like sodium phosphate- which changes the pH of meat protein and allows it to hold more water and weigh more.  “Still wiggling” so to speak, the wet and fresh steak or what have you undergoes treatment with other chemicals, gasses and perhaps radiation, before it is hermetically sealed in shrink wrap and crated for shipment.  While in transport to a retailer, this commercial beef with which we are acquainted is euphemistically referred to as “wet aged” beef.


chopped from U.S. Department of Agriculture poster

Dry aged” beef on the other hand is where a side of beef hangs in a refrigerated meat locker for many weeks as it tenderizes.  The meat locker is maintained just above freezing (34 – 40 deg F), allowing oxidization of fats and enzymatic breakdown of muscle proteins to occur.  Meanwhile gravity pulling upon a side of beef is considered to assist in fiber tenderization.  Only superior beef carcasses with good marbling (streaks of fat interlaced throughout the meat) are subjected to the expense of dry aging.  Dry aging allows time & environment for enzymes to break down muscle proteins into shorter fragments.    Exposed to free air, fat oxidizes and adds flavor to the meat.  Since the process requires extra time, storage space, electrical refrigeration and causes a split carcass to loose a good deal of weight through dehydration –aged prime beef cuts are uncommon and expensive.

Processing Pork

Pigs are very efficient animals to farm for slaughter because the majority (>87%) of their weight is converted to food.  A pig’s skin is often converted to food whereas a cow’s skin is not.  Pork lends itself better to salt curing preservation than does beef or large, lean wild game.  On the American frontier the hog was a cost-effective animal that was almost indispensable to early settlers.  Pigs thrive in most climates, eat almost anything and reproduce quickly.  With just a few pigs, farmers could feed their families through the winter, sell some or stash some extra meat away in storage and still have lard leftover to make things like candles or soap.  (* For candles, alum & saltpeter were added to harden tallow.)

* Noting the Jewish and Islamic taboos on eating pork, the restrictions probably made perfect sense to earlier civilizations in the warm Middle East.  Pigs can carry several types of parasites or viruses.  Trichinosis comes to mind but this encysted larva of a parasitic roundworm might be found in almost any type of wild mammal also.  Omnivorous pigs do have a more basic and quicker acting digestive system than do cattle (or humans), and they have no sweat glands to expel pollutants they might have ingested Pork is one meat that definitely should be cooked well.  That means reaching 71° C (160°F) temperature down deep next to the bone in a piece of meat.  From New Guinea to Hawaii the ancient Polynesians cooked pork in a pit; usually to a point where the meat just fell away from the bones.


People who raise pigs for easy slaughter might prefer their shoats to be of manageable scalding size – say 45kg (100 lbs.) or so.   Immediately after killing a pig, “sticking the pig” refers to puncturing its carotid artery with a knife to let the blood run out quickly.  Since retaining the skin is often desired, the easiest way to remove the hog’s hair is probably to scald the carcass in boiling water.   Next the hair should be scraped off with a blunt edge tool similar in sharpness to the backside of a butcher knife.  Afterwards flame can be used to burn off any remaining individual hairs.   Actually surrounding a pig’s carcass with dry straw and setting the pyre afire is an ancient alternative to hair removal by scalding.

After scraping, the pig’s carcass is often hauled up into a tree by its separated hind legs.  This allows the blood and other fluids to drain, allows for easy separation of the offal and facilitates simple splitting of the carcass down its backbone.   Splitting down or through or beside the hard vertebra requires a tool like a hacksaw, reciprocating saw or heavy butcher’s  (not a flimsy Oriental type) meat cleaver.


* Butchering can be preformed on a flat table also.  The following link to a video shows a skilled butcher doing just that.   Whole Pig Butchered Video

*Another video showing where bacon is located and how it is cut.

After being processed to the point of being split into halves or smaller “primal cuts” there are several avenues to take:  as in choosing between barbecuing, canning, freezing, etc.  This post is concerned with exploring the old fashioned smoke & salt cure methods of  long term preservation.  The majority of traditional curing recipes were intended to complement pork coincidentally.

Typically a ham or shoulder might be packed in dry salt cure (1 lb. for every 12 lbs. meat) and remain that way for at least (2 days per lb. of meat).  The same cut would remain submerged for about twice that long for a brine cure – or a month max.  Thinner bacon or loin cuts would differ by requiring about half as much salt cure.

For the thick ham and shoulder cuts a “brine pump” is very useful in preventing rot, by injecting cure solution down deep next to the bones.   Length of smoking period is a matter of taste, with 4 days being a minimum and no limit on a maximum exposure.   Virginia hams, already cured, might yet hang in a smokehouse for years.  Back in Colonial American days these hams were valuable and articles sometimes needing protection from theft.


* “Boston Butts” or cuts of pork do not come from the rear end of a hog – just the opposite.   The name comes from colonial America and the way that these tender shoulder cuts were packed for export and in salt, within smallish or middling sized wooden kegs (the cask themselves were referred to as butts).  

Usually an experienced butcher will separate the loin and belly sections from the shoulder (top butt and picnic) section by cutting down between the 5th and 6th ribs.   Ribs are counted, beginning from the neck.  The loin region ends at the last rib.  The tenderest meat from either a pig or a cow comes from the tenderloin.  The tenderloin is a long muscle that doesn’t get much use, and it runs inside the rib cage and alongside the spinal column.   The “Filet mignon” cut steak comes from the smaller end of this muscle (the end further away from the hip).  The expression “Living High on the Hog” refers to eating or being able to afford the most tender and therefore most expensive cuts of meat.   As with cattle or any similar herbivore, meat generally gets tenderer as the distance from the hoof grows.


hash of 4 altered public domain images


Horses normally have 18 pairs of ribs, but occasionally 19 pairs.  The first eight pair of horse ribs are “true ribs” and the other ten are “floating ribs”.  Pigs have 15 to 16 pairs of ribs – depending upon breed.  For comparison humans generally feature seven “true” plus five “false” ribs, for a total of 12 rib pairs; except for an occasional human who may possess a pair less or a pair more than normal.  Cattle have 13 pairs of ribs.  “Chuck” cuts of meat come from the area surrounding the first five ribs on a side of beef.  In the U.S., “Rib” cuts of beef come from the area between rib #6 and rib #12.   The last or 13th rib marks the beginning of the loin region.



The bits and scraps of meat and fat left over after butchering are not wasted but put into sausage.   Traditionally the small intestines of the animal in question were washed carefully and stored in brine until used as the casings for stuffing.   Cleaning intestines is a tedious job as both sides have to be carefully scraped of fat and mucus.  Everything must be rinsed several times.   Someone today might opt to purchase artificial casings or perhaps purchase real hog or sheep casings on-line or from a butcher.

Any type of meat can be used alone or in combination to make sausage.  The happy balance between meat and suet in sausage seems to be somewhere around 2 parts lean meat to 1 part fat.  Too much fat makes a greasy sausage that shrinks, while too little makes hard and dry sausage.  Sausages can be hard cured and preserved for long periods, eaten immediately or frozen.  Seasonings to avoid if freezing sausages would be garlic, sage and salt.  Somehow the freezer makes the garlic tasteless and causes the other two to produce bad taste.

Besides casings the only other item needed to make sausage is a machine to grind up the meat.   Food processors can perform this function but leave the particles too small.   Expensive electric meat grinders perform admirably but are overkill for the occasional homespun sausage maker.  The ideal sausage grinder for occasional use might be a hand cranked model, invented over a century ago.   Smaller black & white reproductions of this approximately 117 year old poster below were probably placed in mail order catalogs.  A  funnel shaped attachment for stuffing casings accompanied the product.   Copies or clones of this chopper are still being manufactured today.


Disease, toxins, worms and other nasties

Toxins or “biotoxins” are the poisons created only by living cells or organisms (all other poisons are correctly referred to as toxicants).  Some pathogenic viruses, bacteria or fungi may require oxygen, while others do not.  Acidity or the lack of, radiation like x-rays or UV light, freezing temperatures or high cooking temperatures and chemicals like salts, can all deter the detrimental effect of biotoxins in food.  There are at least two hundred different known diseases or maladies, transmitted through food to worry about.  Only a few short descriptions are listed here…

Clostridium botulinum which is responsible for botulism, is killed or inhibited by saltpeter (NaNO3 or KNO3), oxygen and high cooking temperatures. The most lethal neurotoxin ever discovered by mankind is named after a Latin word meaning – sausage.  “Sausage poisoning” was once more common than it is now.  A can of improperly cooked peaches may produce botulinum toxin.    Although it can kill quickly, contracting botulism these days is very rare, something like 10 cases a year in the U.S.   <see Alaskan Eskimos>   The bacterium is found throughout the world in the soil and in untreated water.  Some vain people actually pay a cosmetic dermatologist to inject this deadly protein into their face <see Botox> , where it has the effect of weakening or paralyzing facial muscles and removes wrinkles.  The toxins created by this bacteria are inactivated by cooking to 160 deg. F.   The bacteria itself is killed by 175 deg. F temperature but the dormant spores themselves won’t be killed until 250 deg. F is reached.

Salmonella is caused by eating food contaminated with animal feces.

Campylobacter jejuni is the most common cause of bacterial foodborne illness in the United States.

Listeria or Listeriosis is caused by the Listeria monocytogenes bacteria  and is the third-leading cause of death among foodborne bacterial pathogens.

Escherichia coli (E. coli) are bacteria that live in human and animal intestines.

Trichinosis is a fairly rare (now) parasitic roundworm disease, caused by eating undercooked meat containing the worm’s  larva.  New strains of this parasite have been discovered that are found even in birds and crocodiles.

Toxoplasma gondii is a parasite that is the second leading cause of deaths attributed to foodborne illness in the United States.  It is one of the more common parasites in the world and affects about 1/3rd of the human population.   The parasite goes to the brain and forms cysts.  Laboratory rats affected by toxoplasma gondii loose their innate fear of cat urine odor and the males begin to produce more testosterone.

Hepatitis E is a liver disease caused by a virus transmitted by fecal contamination in water or food supplies.

Chemical Additives

Without food science and the shortcuts taken by Big Food and Big Pharma corporations, we could not sustain our present standard of living, nor feed ourselves- our masses as we do.   Not too long ago, almost all edible foods came from farms.  Today’s food however is largely produced in factories.  This processed factory food is chock full of questionable chemicals and additives.  Be assured that most of these additives are safe from a chemist’s perspective.  Intermittently however, new research uncovers dangers and unintended consequences associated with ingestion of these ‘safe’ food additives.

Sodium phosphate commonly encountered as approved STP (Sodium Tripolyphosphate) allows meat to hold more water.  This is good for the seller who pumps this stuff into meat and bad for the buyer who must purchase meat by weight.  To be fair, phosphates do help extend the shelf life of meat and dairy products like cheese by restricting the development of rancidity.  Phosphates are under suspicion however of increasing the risk of kidney disease, high blood pressure and heart disease.

Sodium Lactate also increases meat shelf life and can be expected to benefit color and taste.

Sodium Erythorbate, Erythorbic Acid and Sodium Isoascorbate are added to meat to preserve its color.   Keeping meat pink is a big thing; carbon monoxide gas is also used for this purpose as were sodium or potassium nitrites before the 1970’s.

Monosodium Glutamate (MSG) is an amino acid that makes meat and other food taste better.   It allows companies to perhaps put less real meat into packaged food.   Irregardless to brain damage caused to mice, baby- food makers of the 1960s put MSG into those little jars to influence the taste buds of parents.

Potassium Sorbate and Sorbic Acid inhibit mold growth on jerky, sausages, cheese, syrup & jelly.

Sodium Citrate which is a crystalline salt derived from citric acid fermentation or by the neutralization of citric acid with sodium hydroxide.  It’s been recently approved for use in meat products as a preservative where it slows spoilage from microorganisms.  Salty and tart in taste – it maybe used to flavor soft drinks and juices or be employed as an emulsifier.

Hydrolyzed vegetable proteins are used as Meat Flavor Intensifiers (MFI)  and boost or increase the meaty flavor of meat items, gravies, and sauces.

Ractopamine hydrochlorid  is not a chemical added to meat.  Rather it is a growth enhancer, fed to livestock, which increases profits by requiring less feed.  Quickly grown cattle fed this growth enhancer develop lean meat.  Chickens and turkeys fed stuff like this often develop over-sized hearts, kidneys and livers, and grow so fast and get so heavy that they become immobile and cannot carry their own weight.  Cattle and pigs fed a diet of ractopamine have developed abnormal lameness, bloat, breathing disorders and hoof disorders.   Approved in countries like the U.S., Canada, Mexico, Japan and S. Korea – ractopamine hydrochlorid enhanced meats are outlawed in the EU, China and Russia.

Transglutaminase (TG or TGase) is an enzyme that bonds protein molecules together.   First identified in 1959, it took another 30 years to find an economical source and exploit this ‘meat glue’.  “With meat glue you can glue any protein to any protein”.  “Gluing chicken skin to salmon works quite well….. and will actually protect the outside of the salmon from overcooking”.  <Frankensteined meat> 

Saltpeter can refer to several separate substances, most of which were strategic materials for making propellants and explosives in the 18th & 19th centuries.   Sodium nitrate (NaNO3) is the compound most usually identified as a meat preservative, but also potassium nitrate and magnesium nitrate to lesser degrees.   While regular table salt (NaCl) kills many bacteria like salmonella below 3% solution, much higher concentrations might be needed needed to kill other types of bacteria.   A concentration of about 20% salt soaked into meat would be required to make meat safe from most every type of microbe.   Meat that salty is not palatable.  Somewhere back in time before the Romans, people noted that salt from certain mines preserved meat better, retained its color and made it taste better.  Eventually traces of nitrate (saltpeter) were identified within that or those popular mined salt(s).  The nefarious Clostridium botulinum bacterium was identified in 1895.  Thereabouts it was determined that nitrate salts kill or inhibit the botulism causing bacteria.  Since saltpeter also benefits color retention and imparts a desirable flavor we have been using nitrate meat preservatives every since; up until the 1999 that is.

The U.S. FDA has determined that nitrates are no longer allowed in commercially packed meats, while nitrites are to a limited small degree (for dry cured uncooked products like jerky).  Nitrates and nitrites differ by one oxygen atom.  Ammonia is released into the soil by the decomposition of organic matter, and it oxidizes to form a nitrate or nitrite.    Nitrates themselves are relatively inert and enzymes in the human body convert them into nitrites anyway.  Some vegetables we eat daily are loaded with nitrates, containing far more nitrates that might be encountered in cured meats.  Some athletes might drink nitrate rich beet juice to enhance physical performance.   Nitrites can turn into useful nitrous oxide by losing an oxygen atom or into dangerous nitrosamines, which can be created by high heat cooking.  In the 1970s several studies showed correlations between nitrosamines and cancer in rats.  Since that time, nitrates in curing salts have been studied to an exhaustive degree.  The verdict is that nitrates and nitrites are not carcinogenic.  Apparently nitrosamine formation can be inhibited by ascorbic acid.  Since refrigeration is fairly ever-present today, there no sense in risking the possibility of someone creating nitrosamines by overcooking -uncooked nitrate cured meat.   Individuals wishing to hard cure meat by traditional means can still buy premixed ‘salt cures’ containing either nitrites or nitrates or both.   “Prague powder” is one such cure that is still sold after being invented 80 years ago.

USDA Ham and Food Saftey information.


There are two widely separated forms of meat smoking.   The old way of smoking for long term preservation – is now referred to as “cold smoking”.   The new and widely spreading fad or form of meat smoking encountered these days is called “hot smoking”.

Hot smoking implies drenching meat in humid, flavorful smoke while simultaneously cooking the meat.   Temperatures between 130 and 210 deg F are required for hot smoking.  Since the cheaper and relatively tough cuts of meat are used in this process, the cooking is done slowly; taking a long time under moist heat to breakdown and soften the cartilage or gristle (collagen).    Done correctly those tough cuts become very tender to chew.   Hardwoods like oak, hickory, apple and cherry produce the most flavorful smoke.   Depending upon the fuel used to create cooking heat (wood fire, propane, gas, electric) the smoke might be generated by pellets or moistened wood chips.   Hot smoking is purely concerned with the art and science of cooking delicious, flavorful meat.   It does not impart a preservative effect upon the meat.

Cold smoking has been going on for thousands of years, and for more practical reasons too when considering the historical lack of refrigeration.   Wood smoke imparts preservative creosote to the meat that discourages insects and microorganisms alike.  Wood smoke flavor in an aged hard cured ham or bacon might be intense, but still of a secondary nature when compared to the typical saltiness of that same dehydrated meat.   “Virginia hams” were and still are famous for their flavor but these are often so salty that they need to be soaked and rinsed for 3 days to get the salt out.

Speaking of Virginia hams, Martha Washington (wife of the first American president) was famous for hers.  The plantation at Mount Vernon was typical for plantations of the period.   In addition to a large number of working residents to feed daily, guest and foreign dignitaries were always dropping in for visits.   Martha reportedly set a good table.  She also took pride in her hams, oversaw their curing process and shipped many away as gifts, some across the ocean.   Two hundred years ago working plantations like this had crews to maintain large continually smoking smokehouses, which were packed with beef, pork, mutton, ducks, geese, fish and anything else they could find.

Famous uncooked, hard cured, smoked Virginia hams are available for purchase.   These and some others like them are intended to be cooked, however some even more prominent European hard cured hams are usually eaten raw and are still allowed to be imported to the U.S.  (Ardennes Ham from Belgium, Jamon Iberico & Jamon Serrano from Spain, Prosciutto from Italy,  Westphalian Ham from Germany and sometimes York Ham from England – for example).


I am neither a chemist, physician nor an authority on the safety of consuming uncooked meats.   All I can do is observe and realize that decisions made while preserving meat in traditional ways, do carry some risk and should not be made lightly.

Somehow this particular post took a detour and became somewhat longish.   The title will be truncated from “Curing meats & Tanning hides” to what you see now.   The last image from the post preceding this one featured a tiny homemade cold smoking apparatus featuring a venturi.  The background of that fabricated image features a (lost) drawing of an industrial smokehouse, the type of which might have been found in any city of size, before artificial refrigeration was realized.   Wood smoke was also used to preserve leather, a trick American ‘Indians’ were fond of.  Rawhide and leather though, are fodder for a future post


Hot Stuff 3 – Rocket stoves to meat smoking



Versions of the “rocket stove” principle have been manufactured for about 90 years, so the concept must be older.  Above is a cheap and quick example of a rocket stove made with about seven tin cans.  The barrier between the inside chimney of small cans and the outside layer of large ones, is insulated with sifted wood ashes.  Rocket stoves are efficient for cooking because they burn hot and use very little fuel.  The “rocket” name undoubtedly stems from the vigorous manner in which air, flame and smoke are all drawn into the chimney.


For free standing little cook stoves and water heaters the optimum chimney height might be a little less than three times whatever inside diameter is actually chosen for the chimney.   These proportions seem to engender the best draft.

Once a fire has been ignited it takes a few minutes for the stove to become normalized.  Once hot and working correctly these little stoves consume almost all the volatiles in smoke and leave little pollution.   Using just dry twigs these stoves are capable of reaching 1,600 – 1,700°F (926°C).    * That’s a temp high enough to melt tin, lead, zinc, antimony, magnesium, aluminum and lava – but not silver, gold or copper.

Iron stoves or the ‘tinplate’ steel found in a soup can will not stand up to long term heat of this degree because of the accelerated rate of oxidization.   For this reason a stainless steel, ceramic or refractory version would be desirable for stove longevity.


Slick stoves working upon the rocket principle have been made with cinder blocks and stacked bricks.  This link is to a rocket stove manufactured in China.  These are practical products but seem a bit costly.


A long lasting cementatious rocket stove can easily be made at home.   This image (idea robbed from a video) depicts creating a mold from plastic sewer pie and a 5 gallon plastic bucket.   Yes the mold could be filled with plain cement but a refractory mix would be more desirable.   A concrete rocket stove would conduct heat and become hot to the touch and would also be heavy to move.   A stove cast of proper refractory would be lighter weight and insulated, allowing desirable higher heat inside the chimney.

Opinions and examples of refractory mixes vary widely.   Perlite and vermiculite are frequently listed as light weight insulating ingredients in refractory mixes.  If the intended function is not too demanding, wood sawdust or peat moss might substitute as the light weight, insulating ingredient.  Perlite is a volcanic glass that has been ‘puffed up’ like popcorn (with the help of escaping steam when it was created).   You’ll frequently find little individual white beads of perlite mixed in with commercial potting soils, or sold in bulk at plant nurseries as a soil amendment.  Exfoliated vermiculite possesses many of the same qualities as perlite.   Fireclay is an ingredient used in the refractory of brick, ceramic and glass kilns, because few other building materials can repeatedly withstand such high working temperatures.   An easy to remember recipe for an adequate refractory mixture would be four equal parts each of sand, Portland cement, fireclay and perlite (or vermiculite).  Those proportions could be tweaked a bit to reduce sand and cement (1.5 sand, 1.5 cement, 2 fireclay, 2 perlite).

When casting a mixture like this it is important to use as little water as feasible to ensure the strength of the concrete (refractory).  Do not forget to allow adequate space at the bottom for insulation of the chimney and remember to tamp this first, with a stick, before filling the remainder of the mold.   A wire skeleton or armature of some sort would greatly enhance the long term resilience of such a cast.


Two centuries or more ago, the chimney in the center principle was being exploited by expensive handmade self heating teapots known as samovars.   Manufactured portable utensils for heating or sanitizing water outdoors began to be seen in numbers for the first time however during WWII, when the New Zealand Army issued their soldiers with mess kits containing jacketed kettles.   ‘Storm kettles’ or ‘volcano kettles’ work well in windy or rainy weather.  Fuel from twigs to straw to buffalo chips can be found almost anywhere and cost nothing.

Not commonly found in American sporting goods stores, these kettles are made by several little companies and are produced in either aluminum or stainless steel versions.   Rather than pack into the woods a stove that requires special fuel (sterno, denatured alcohol, hexamine tablets, paraffin wax, kerosene or  naphtha (white gas)) it seems more logical to carry one that simply uses fuel which can be picked up from the ground.

Thermette:  Ghillie-kettle:  Eydonkettle:  Kellykettle



For some time now some people have been using a larger form of the rocket stove, known as a “mass heater”, to warm the home.  In this case the exhaust from the chimney is captured and turned downward, then circulated through a wall, the floor or a banco (bench).   The masonry in the wall, floor or bench acts as a thermal mass or heat sink that collects the heat and releases it slowly.  So from the illustration above an oil drum or other metal hood accomplishes the first heat exchange to the room’s atmosphere.  Any remaining heat is ideally captured by a thermal mass before the exhaust is finally released to the outdoors.

A few examples of these thermal mass heaters are found almost all over the world.  It would be very feasible to pre-heat water for the home by wrapping a water line around a rocket stove’s chimney.   Potential construction concerns for building a mass heater of this type include ensuring that the draw of the stove is sufficient to push exhaust through a long ductwork.  One critical dimension is the distance between the top of the chimney and the hood (drum).   Some people brag that the amount of firewood needed to warm their house was reduced by 75% after resorting to a ‘mass heater’.   One should consider however the extra time spent splitting wood into pieces small enough to feed into this stove, and the extra attention probably required to keep the (fast burning) stove continually fed.   Depending on size it may take several hours to several days to equalize the thermal mass, so hopefully in the meantime the house would be equipped with an auxiliary source of heat.


Added 7/27/2016

The rocket stove mass heater takes its idea from the much older masonry stoves and or ceramic stoves of Europe and Russia.  Usually constructed of brick and covered in tile these often massive heating appliances are at least one thousand years old in design principle yet are still “greener” and more efficient than modern heating alternatives. 

The typical “tulikivi” (Finnish), “kachelöfen” (German), “kakelugn” (Swedish) or “pechka” (Russian) oven stoves only need to be fired about twice a day to provide a continuous 24 hour heat.  In some homes the people sleep on them, or may also bake with them.   When designed well they burn very hot and therefore leave little creosote buildup behind.   Inside the fire’s exhaust must furl around a labyrinth of baffles before it can escape, providing time and surface area for energy transfer.


In the last century or so of newer building construction, massive masonry heaters like these were usually replaced with much smaller coal, oil or natural gas burning alternatives.   

The cast iron wood cookstove became a favored house heating appliance in America homes between the 1870s and the 1920s.  They were advertised in newspapers and mail order catalogues and were manufactured by a host of different companies like ACME, Acorn, Garland, Majestic, Monarch, Peninsular, Pilgrim and Sterling.  These wood stoves or ranges could act as energy centers perhaps for the whole house and they supposedly baked a better loaf of bread than any modern gas or electrical counterpart.   Different models came with different options including ornate chrome (probably nickel) trim, hot water reservoirs, foot latch, thermometers, broiler drawers and secondary warming ovens.   Cooking on such a stove could require much patience to establish the fire, because in addition to the firebox some models came with an adjustable main draft regulator, check draft regulator, stove pipe damper and an auxiliary damper.  It was standard practice for a housewife to keep a stock pot on the back of the stove, where she put leftover scraps of meat and bone.   Comfortable and desirable in the winter – these stoves could become beast to cook with however on hot summer days. 


 Pertinent links-

Tile stoves

Masonry heaters

New wood stove



After reconsideration the project on the right above will be redesigned from an “L” shape to a “J” shape, to allow fuel to be fed from the vertical axis.   Sheet metal screws will be reversed so that they can be removed from the inside.  After that cans are to be wrapped in plastic food wrap and a chicken wire armature will be wrapped around the cans – suspended about an inch away.   After that a refractory mix will be slathered over the armature to a depth of about 2 inches.    Some of the metal cans will be too hard to remove initially, until years afterwards when the rust can then be pulled from the refractory easily.

(Slideshow below added August 2016)

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The image above is a little incongruous with the topic of rocket stoves, but since it is related to fire and cooking and was available, it is included now.  Methods for cold meat smoking are diverse and numerous.  This image depicts a homemade variation of a commercial product which blows a steady stream of wood smoke into a meat holding chamber.   The main feature is the venturi which in this case is powered by a tiny air pump (like one used to aerate a fish aquarium).  The can below the homemade copper venturi needs a lid that will open and close; to insert wood chips or remove ashes.  The can needs some holes in its bottom so that combustion air can be drawn up through the smoldering woodchips.  Twelve to sixteen ounces of (hardwood) wood chips should provide about three hours of smoke.

There is not enough time and space left in this installment to adequately explain the important details of meat curing.   Remember that the wealthier half of civilization has only possessed artificial refrigeration for the last century or less.   Salt and smoke dehydrate -bloody raw meat.  Salt and smoke and cold weather have historically been the preferred tools for preserving meat by protecting it from bacterial spoilage.  Traditionally, smokehouses worked continually around the clock and pretty much throughout the year.  It is recognized by some that today’s commercial hams and bacons will putrefy long before they should (had they been properly cured and smoked by traditional methods rather than by quick methods).

In 1832 it was discovered that pyroligneous acid from creosote in wood smoke was the antiseptic preservative which protected meat.  Today commercial meat processors commonly inject into boned meat, salt, nitrites, nitrates and sulfides.  Before slaughter the animal may have been fed antibiotics, steroids or additives like ractopamine hydrochlorid.  About 70% of all chicken and beef sold in the U.S. and Canada is actually treated with carbon monoxide before you buy it.   The best way to tenderize meat without resorting to chemicals, is to cook it slowly.  Nowadays the best reason for treating meat to wood smoke (longer is better) is for the taste.

A Primer on Explosives

It has been repeated so often that it is now accepted as fact that the Chinese invented black powder around the 9th century AD.   This may be the truth or it may be a myth perpetuated after Marco Polo wrote memoirs of his 13th century experience in the East.   There is actually some evidence so suggest that gunpowder may have actually originated in Greece or India.  It is not disputed that the Chinese were apparently the first to show significant progress in the refinement of black powder and the development of fireworks, the first to propel rockets and the first to attempt to intimidate enemies with explosives.


Introduced in 1961 the RPG-7 imaged above shares several admirable qualities with other Russian weapon designs; namely it is cheap, uncomplicated, efficient and rugged.   This rocket grenade launcher is encountered around the world and has been involved in most every armed conflict of any consequence for the last 40 or 50 years.  In Somalia or Iraq such a weapon might be acquired for about $200 and additional rockets might cost about $20 to $30 apiece.   In black markets of other parts of the world an old and worn RPG-7 might command about $1,000.  A standard HEAT (High Explosive Anti Tank) rocket as shown in this image would be obsolete and ineffective against modern tank armor but still devastating against softer targets.  Fragmentation grenades and small thermobaric warheads are also available for this launcher.   In the image the solid booster charge, solid rocket propellant and the unlabeled conically shaped HEAT warhead are all “explosive” or are potentially detonate-able although the first two chemical compounds merely deflagrate in a controlled manner.

Deflagration vs. Detonation

For a chemical to be considered explosive it must rapidly form gases and heat and exhibit the ability to be initiated by shock or by heat.  Chemical explosions are simply accelerated rates of chemical decomposition.   A campfire is an example of chemical decomposition as is gunpowder burning in a shotgun barrel.  Gunpowder, fireworks and air-fuel mixtures in internal combustion engines are “low explosives” and examples of “deflagration”.    Deflagration (from Latin – “to burn down”) is a rapid but subsonic (342 m/sec or less, 1,126 ft /sec or less) decomposition where a combustible and an oxidant are reacting at the molecular surface area, called a “flame front”.   The fake looking explosions in most Hollywood movies are examples of deflagration; where pyrotechnic stunt coordinators make big yellow-orange fireballs by setting off containers of gasoline.   In contrast, “high explosives” exhibit detonation.   Detonation is a supersonic reaction where a “shock front” rather than a flame front, travels through the explosive.   Detonations propagate through shock compression and can reach speeds of up to 9,000 meters/sec (29,527 ft. /sec).

* For comparison the fastest bullets or shells from rifles or cannons have a top speed of about 4,000 feet/sec (1,219 m/s).  Although the unconfined propellants do not deflagrate that fast, the buildup of pressure confined, accelerates the projectiles to that speed. 

* If detonated at the same instant that a fast bullet was fired from a rifle, a six mile length of primer cord filled with an explosive like RDX (which has a high detonation velocity),  would have vanished in its entirety before the bullet had gone one mile.  

* Without the confinement of a barrel and closed breach, a loose rifle or pistol cartridge when tossed into a fire – would pop like a child’s firecracker and be about as dangerous.  The brass case might split, some coals will be thrown around and the bullet may or may not bounce a few feet.


The caption or information included in the following video explains that it displays the destruction or disposal of a solid fuel rocket motor from a retired ballistic missile.  The caption claims that 38,000 lbs of HD 1.1 propellant are detonated.   HD 1.1 (Hazard Division 1.1) implies a nitramine-based explosive like RMX or HMX (both are commonly used for solid rocket fuels as well as components in the lion’s share of modern military grade plastic explosives used by the US and GB).

Huge Explosion and Shockwave

The problem with this video is that at this level of camera zoom, the supersonic shockwave or blast wave passes too quickly to be seen.  What can be seen and what is erroneously referred to as a shockwave is actually the transonic sound wave.  The camera was filming from about a mile away, which can be verified by the fact that the shadow and sound (which travels about 1,125 fps) took about 5 seconds to reach the camera.

This following ho-hum video, appears to be a clip from a TV show.   Some impression of shockwave is captured by high speed cameras.

Huge Shockwave Captured at High-Speed | 

More shockwave information:


Brisance, Stability & Sensitivity

    Brisance is a French word meaning “to break”.   The brisance or the shattering effect of an explosive is proportional to its speed of decomposition but is not a total measure of the compound’s work capacity.  Relative brisance between explosives might be determined by field testing or sand crush test.   Knowledge of relative brisance is useful to bomb and fragmenting shell design engineers or to Army engineers preparing to destroy bridges, bunkers or other structures.

Stability refers to the ability of an explosive to be stored without deterioration.  There is a large variation in the stability of various explosive chemical compounds.   Fulminate of mercury as used in the priming compounds of rifle or cannon cartridges might be considered to have a good stability.   A high percentage of mercury fulminate primed rifle cartridges from the WWI era might be expected to perform (if they were stored well) even though they are now approaching 100 years in age.   On the other hand, long stored nitroglycerin has a reputation for separating from the other constituents in dynamite.  Such old dynamite becomes “unstable” because it deteriorates; the nitroglycerin collects as a liquid and becomes dangerously “sensitive” again.   TNP (Trinitriphenol or picric acid) which was once used as a primary explosive in naval and land artillery shells prior to WWI, eventually tended to corrode the metal shell casing it was housed in and created new and dangerously sensitive chemicals.

Heat, friction and shock test are preformed on explosive compounds to determine their sensitivity rating.  Actually the scale used to gauge the relative sensitivity of different explosive compounds is called the “Figure of Insensitivity”.   For many years this scale was based upon the sensitivity of TNT which is very insensitive – with a rating of 100.  After the creation of faster explosives in WWII, TNT was supplanted as the most common comparison gauge by the more sensitive RDX (with a rating of 80).

* Invented way back in 1863, TNT (or trinitrotoluene) was so insensitive that it was a challenge to make it detonate.  It was used as a yellow paint pigment for 40 years before it finally saw use in munitions.  It was notorously toxic for factory workers to handle and still being manufactured today. 

It is useful to understand that the blasting agents which provide the horsepower of an explosion are seldom if ever used alone and that a chain (or train) of reactions is usually necessary to produce the desired blast.   Common explosives like dynamite, TNT, and C4 are so insensitive and safe to handle that they require a substantial physical shock to set them off.   The first stage in an explosive train is a small and sensitive “primary explosive”.   Once stimulated the less sensitive “secondary explosive” might be the end of a train or the stimulant to set off an even more insensitive third stage.  This final or tertiary stage provides the real horsepower in such a chain, and might consist of a very insensitive blasting agent like a compound of horse manure and diesel fuel or ANFO (Ammonium Nitrate and Fuel Oil).   In essence a lowly firecracker can be the initial stage of an explosive chain leading up to the eventual detonation of the mightiest thermonuclear device.


Igniters, Blasting Caps & Detonators

Commercial and military detonators might comprise a little explosive train in their own right, containing perhaps three separate compounds.  The most common primary explosives used in today’s blasting caps & detonators are DDNP (Diazodinitrophenol), mercury fulminate, lead azide, lead styphnate and tetryl (until recently).   Potassium chlorate and potassium perchlorate were once used in explosive primers and detonators.  Today’s blasting caps might house small – less sensitive secondary charges of PETN or RDX perhaps.

* Compounds like nitroglycerin and silver fulminate are simply too sensitive to safely handle.   Other compounds can be used as primary explosives but are seldom used in modern detonators for various reasons.  These would include:  acetone peroxide, ammonium permanganate, azo-clathrates, copper acetylide, HMTD, lead picrate, nitrogen trichloride, nitrogen triiodide, silver azide, silver acetylide, sodium azide, tetacene, tetrazoles and triperoxide.      

* Apparently the first blasting cap was realized in 1745 and consisted of black powder which was set off by a spark from a Leyden jar.   Later in 1750 Benjamin Franklin created a better blasting cap by stuffing two parallel wires and black powder into a rolled paper tube.  The first glowing “hot wire” detonator appeared in 1822.  The first pyrotechnic fuse blasting cap was created in 1863 by Alfred Nobel.  It used a burning fuse and mercury fulminate to detonate his relatively insensitive and patented, nitroglycerine based mining explosives.   Five years later someone else invented the first electrical blasting cap capable of detonating dynamite (this combined mercury fulminate and a spark gap igniter).   

* Today pyrotechnic fuse and fuse caps (more modern metal tube equivalents of Nobel’s original wood tube) are becoming rare because older explosives like dynamite and gelignite (blasting gelatin) have largely been displaced by more modern and usually cheaper alternatives that might also leave less noxious fumes behind after a blast.  Even electrical blasting caps are becoming less common for certain types of blasting; the wires are being replaced with little plastic air tubes.  Avoiding radio waves and static electricity, these tubes transfer shock to the primary explosive using air pressure. 

Military detonators are usually a bit stronger than their commercial counterparts.   Today #6 and #8 caps are the only commercial blasting caps mentioned.  A # 8 cap is traditionally about twice as powerful as # 6 and would be used for initiating less sensitive explosives.  There is no such thing as a commercial # 4 blasting cap, but had it existed it would have reflected the power of a cap containing .4 grams of mercury fulminate.  Cap  numbers less than 6 are apparently not made and cap numbers stronger than 8 don’t exist or have no convention standards.  There may have been a time when mercury fulminate was the only substance used in blasting caps but before long potassium chlorate began being mixed with it.  Potassium chlorate was cheaper than and enhanced the power of the mercury fulminate.  A traditional # 6 blasting cap of yesteryear contained .2 grams of 80/20 primary (fulminate/chlorate mix) and .4 grams of a booster like PETN.  A traditional No. 8 cap would have differed by housing twice the PETN.   Modern # 8 caps have increased substantially in power depending on the source and have become the common types, but there is a lot of variance in what is termed a # 8 detonator.  A “US Army (Engineer’s) Special Blasting Cap” or “Military No. 8” for example might contain as much as 13.5 grams of PETN or RDX.

A matchhead or firehead electrical blasting cap uses an electrical match that sits in a pyrotechnic ignition mix in the butt of the cap.  An electric match is nothing more than a thin wire with a dollop of substance like dried red phosphorus attached to it.  It is a wire that gets hot and basically ignites the equivalent of a ‘kitchen match’ and starts the explosives train.   Only 3 volts from 2 flashlight batteries is required to set off the simple electric matches or ‘engine starters’ of solid propellant toy rockets.   Multiple exploding bridgewire detonators are generally used to uniformly initiate the primary stage of a nuclear weapon.   In effect a high capacity electrical discharge vaporizes each very thin bridgewire which in turn initiates a shockwave that simulates the chemical reaction.  The Germans were the first to use this type of detonator with their demolition charges in WWII.


*Explosions that detonate or deflagrate produce a lot of gas.  A mole of a substance is its mass in grams, as determined by the atomic numbers of its constituents and at standard temperature and atmospheric pressure a mole of any kind of gas occupies the same 22.4 liters of volume.   Using nitroglycerine as an example: one mole of nitroglycerine (@ standard atmospheric pressure) produces about 7.25 moles or 162.4 liters of gas.  One gram of nitroglycerine (about the size of a pencil eraser) would expand enough to fill a 43 gallon container with gas after decomposition.  The products in this example will be about 3 parts carbon dioxide, 2.5 parts water vapor, 1.5 parts nitrogen and 0.25 parts oxygen.

* Oxygen is essential for combustion and without it explosive chemical decompositions would go nowhere.   Oxygen is not a fuel, but an oxidant.   Concentrated sources of oxygen support rapid combustion.   Peroxides, nitrates, chlorates, perchlorates and dichromates all donate oxygen to combustion.

* Liquefied oxygen is about 840 times as dense as gaseous oxygen.  If spilled, liquid oxygen might soak into porous asphalt, charcoal, wood or petroleum products which then might become dangerously explosive for a short while.

Chemical jargon

Chlorates, perchlorates, nitrates, fulminates, permanganates and peroxides can be thought of as oxidizers with weak bonds and negative charges.

Chlorates are the salts of chloric acid (HClO3).  Combustibles like charcoal, certain metals, organic solvents, sawdust and sugar will easily deflagrate when mixed with a chlorate salt.  Many fireworks in the past were composed with mixtures of chlorates, with various combustibles providing different colors and effects.  In modern fireworks, more stable perchlorates have replaced chlorates as the oxidizer of choice.

Perchlorates are the salts derived from perchloric acid (HClO4), and they are often produced by the electrolysis of chloride salts.  Aside from pyrotechnics, perchlorates are also used in automotive airbags and as solid rocket fuel.  The Space Shuttle launches were powered by two solid rocket boosters that each held 350 metric tons of ammonium perchlorate.

–  The nitrate ion (NO-3) is formed when nitric acid and an alcohol are joined.  A nitrite (NO-2) is the salt of nitrous acid and not the same thing.  The molecular formula for nitrous acid is HNO2, while the formula for the much more significant nitric acid is HNO3.

–  Fulminates contain the relatively unstable fulminate ion (CNO-).

–  A permanganate is an oxidizing compound containing the manganate ion (MnO4-).

–  Peroxides are oxidizing compounds with the oxide anion (O2)-2 or single bonded oxygen to oxygen atom.   Hydrogen peroxide (H2O2) should be called hydrogen dioxide.   Barium peroxide is used in military “tracer” ammunition and in other pyrotechnics while triacetone triperoxide (or TATP) is a hard to detect.  TATP (or acetone peroxide) is easily produced, sensitive and fairly unstable but popular with terrorist like the would-be “shoe bomber” in 2001.  The shoe bomb had a dry TATP detonator along with PETN as the secondary explosive.   Perspiration made the fuse damp and the odor of several matches gave the imbecile’s intentions away.   The ‘hypergolic bipropellant’ of the remarkable WWII rocket-powered fighter aircraft (the Messerschmitt Me 163 Komet) was mixed from “C-Stoff” (a methane-hydrazine fuel) and a high test peroxide oxidizer called “T-Stoff”.   “Hypergolic” means that the propellant components spontaneously ignited when combined.  In field test and during the short carrier of the Me 163 during the war, several aircraft and many people were lost in explosions when these volatile components were handled.   When dealing with this rocket-plane, pilots & ground crew wore special nylon or rubberized clothing just to keep their flesh from being dissolved by these fuels.

Public Domain courtesy FBI

Public Domain
The Shoe Bomber’s Shoe

Nitramines are generally refer to newer and more chemically sophisticated compounds having bigger molecules, higher density, more of the hard to split covalent bonds and more energy packed into a given space.  While some of the best modern military grade explosives are nitramines, the benchmark for explosive speed and efficiency is still nitroglycerine – invented some 1.7 centuries ago.

– A binary explosive simply implies that two components are required to be combined but individually neither component is explosive.  The insensitive and very common blasting agent ANFO could almost be considered a binary explosive.   HELIX™ High Energy Liquid Explosive Binary Energetic is also an example of a binary.

Reactive elements

In pure form the “alkali metals” (Li, Na, K, Rb, Cs & Fr) are reactive or can be potentially dangerous in their own right.   Lithium hydroxide (as stored) when converted to lithium deuteride is used as a fuel in hydrogen bombs.  Pure potassium (K) explodes when it touches water, while rubidium, caesium and francium get even more violent than that.   The alkali metals are rare, and are never found in a pure form in nature – because they are so reactive.   Sodium (Na) and potassium (K) chlorates, perchlorates, nitrates and permanganates are very prevalent in explosive compounds.   Another group of elements called the “alkali earth metals” (Be, Mg, Ca, Sr, Ba and Ra) are reactive, but not as much so as the alkali group.   Of these, manganese (Mg) is commonly mixed in explosives, calcium (Ca) in calcium carbide makes explosive acetylene gas and barium (Ba) has already been mentioned for its use in pyrotechnics and tracers.   Aluminum (Al) belongs to a separate group in the Periodic Table but it is also fairly reactive (which explains why it is never found as a pure form in nature).   Powdered aluminum is a common catalyst or additive, usually mixed into ammonium nitrate or other explosives to enhance the blast power.

*  Hydrogen (H) which is the lightest and most abundant element in the universe, does burn, and can be considered explosive (if exposed to a flame) in concentrations between 4% and 74% with the surrounding air.   Hydrogen can react spontaneously with fluorine and chlorine.  The main engine of a Space Shuttle burns oxygen and hydrogen.   At full power the flame from one of these engines, is invisible – or nearly so, because it emits light in the ultraviolet spectrum.  Checking a pipe for a hydrogen leak involves looking for an ultraviolet flame – as hydrogen combines with oxygen in the air.   Hydrogen fires are seldom as dangerous as gasoline fires.  In 1937 the famous Hindenburg blimp, which was full of hydrogen burst into flames as it approached its landing.  The visible flames of that disaster were the burning outside skin of the blimp.  The hydrogen gas however rose quickly, carrying the invisible ultraviolet flames with it.  The deaths that did occur were the result of falls or by burns from diesel fuel. 

Fluorine (element #9) is so extremely reactive and electronegative that almost all other elements including some of the noble metals and noble gases will form compounds with it.   Hydrofluoric acid was so dangerous that laboratory explosions killed “fluorine martyrs” (chemist) like flies in the 19th century and it took 74 years of concentrated effort just to isolate elemental fluorine.

Phosphorus (P) is a nonmetallic, very reactive element which has been used in many explosive munitions.  It is an additive to start fires and to create smoke.  It is or was used in kitchen matches, fireworks and in weaponized nerve agents.  This elusive element was discovered about four centuries ago when an alchemist dehydrated his own urine, and then noticed that it glowed in the dark.   In WWI, phosphorus was employed on incendiary ammunition against blimps and aircraft.   In WWII phosphorus bombs were dropped on London to start fires while other phosphorus munitions were used to ignite aircraft, tanks and other vehicles, for smokescreens and for anti-personnel mortar rounds.

* A modern incendiary bomb is likely to employ a thermite mixture of aluminum and ferric oxide. 

Black powder

Throughout its history and up until recent times there was no “black powder”, but simply “gunpowder”.    Modern nitrocellulose based “smokeless powders” have become regular “gunpowder” in today’s parlance while the term “black powder” now invokes the old charcoal, sulfur and saltpeter propellant.   In the previous century the term “flash powder” might have denoted the finely ground and very volatile FFFFFg gunpowder used by photographers to generate more light exposure for pictures.   While originally, firecrackers were made with black powder; today’s firecrackers are usually constructed using a faster burning compound called ‘flash powder’ (with magnesium or aluminum powder and a potassium chlorate or perchlorate oxidizer).

True black powder is messy because only about ½ of the material is burned.  It leaves behind a lot of unburned residue that quickly fouls a weapon.   Most new, so-called “primitive firearms” that are used today are never loaded with true black powder – but instead with a cleaner substitute having equivalent deflagration properties.  The main deficiency of black powder (or similar replacement) lies in its inability to drive a projectile past a certain speed.  Black powder has a relative detonation velocity of 1,312 fps.  Confined in a firearm, its pressure peaks almost instantly and starts to drop even before the projectile leaves the barrel.   In contrast the even slower burning smokeless propellants that replaced it in modern firearms, achieve higher projectile speeds because they produce more gas and continue to push and accelerate the bullet as it travels down the barrel.  Cramming more black powder into a black powder muzzle might speed a bullet up to 1,750 or 1,800 fps, unless the increased pressure ruptures the firearm’s breech beforehand.

In 1275 A.D. the standard recipe for black powder was 1 part charcoal and 1 part sulfur to 4 parts saltpeter (potassium nitrate or niter).   More ideal proportions have been determined to be around 13.5% charcoal, 11.5% sulfur and 75% saltpeter.  Charcoal is the fuel; sulfur the binding agent and saltpeter the oxidizer.  After firing black powder’s fouling or residue is corrosive and purportedly contains carbon and sulfur, potassium carbonate, potassium sulfate, potassium sulfide, potassium thiosulphate and potassium thiocynate.

Many a powder company has disappeared in a cloud of smoke, flame and noise during the crushing stage of black powder production.  Static electricity can easily ignite black powder.  In the manufacture of black powder, metal implements are avoided because they might cause sparks or build up static energy.  Before the process called “corning” was adopted, early black powders tended to separate or sift apart; making them inconsistent and possibly unreliable.  Corning was a process where water was added to the gunpowder and was then pressed out.  While still moist the propellant could either be pressed through a screen to make granules or left to dry as cake that was later crushed into small powder.  Using the corning process the final product became more homogonous and the separate ingredients were bonded in crystalline form.

Crushing the powder into smaller grains created more surface area particulate, more flame front and therefore faster burning. In the old days, black powder was graded in regards to its granule size, from 1F to 5F.   “Fg” powder would be used in something big, like a cannon.   “FFg” was intended for large bore shotguns and rifles.   “FFFg” was the common powder for most rifles.   “FFFFg” was fast powder for pistols and for flintlocks with flash-pans.   “FFFFFg” was rare and very fast and as mentioned, was occasionally used by early photographers to produce light in dark settings.

Although black powder is smoky and pokey, it is still getting the job done after a good 700 years of field testing, on land and at sea.  Every manner of big game including African elephant, rhino and Cape buffalo has been felled by it.  At range, in the right hands, black powder rifles have preformed respectably, even by today’s standards.   In front of witnesses a frontiersman once knocked an Indian brave from his horse from 1,538 yards away (later measured, 0.87 mi), using a 50-90 caliber Sharps.


Another testament of black powder accuracy involves a British made sniper rifle used by the Confederacy during the Civil War.  The Whitworth rifle as designed by Sir Joseph Whitworth in 1856 employed a hexagon bore and a hexagon bullet of .45 caliber.  The Whitworth rifle was apparently accurate to well over 1,500 yards, but very expensive and the Confederacy only purchased a handful to issue to a few chosen snipers or skirmishers.   It seems that Yankee General John Sedgwick was unhorsed by a Whitworth during battle.  Sedgwick was rousting his troops who were hiding from sniper fire.  His famous last words were “They couldn’t hit an elephant at this distance” just before a fatal bullet fired from about 800 yards away, hit him square in the face.

A black powder firearm is a pretty crude weapon by today’s standards but in its simplicity lays a certain elegance and reliability.  Modern weapons require modern ammunition a source of ammunition is important.  If sources of modern ammunition run dry then the weapon becomes useless for either hunting or self defense.   Individuals that know how to reload ammunition might fare better for a while – until their source of nitrocellulose powders, primers and bullets runs out.  A survivalist with a black powder firearm however, with the know-how can mould his own bullets, make his own propellant and probably even make his own percussion caps if needed.   Making black powder propellant is hardly rocket science and sources of information on this subject abound.  The differences in proportions are not too critical. The best homemade gunpowder will probably be inferior to commercial powder but should work.  It should not be considered an act of anarchy or the abetting of terrorism to provide the interested reader with a recipe here.

* The following recipe is a combination of ideas from too separate books (“Special Forces – Guerrilla Warfare Manual” by Scott Wimberley and “The Poor Man’s James Bond” by Kurt Saxon).  The proportions of 6 parts potassium nitrate to 4 parts charcoal and 1 part sulfur would comprise a fine mixture.  If the units of measure were cups then this mix would produce about 4 pounds of propellant (perhaps ½ the measure would be more appropriate).  The different components should be ground separately into small powders before beginning.  Here the methods from the two books deviate.  In one example the three components are mixed with a little water (1 part water – or preferably a better solvent like whiskey or rubbing alcohol) and allowed to set up into a malleable paste. The other method involves using more water (3 parts), heating the mix slowly until small bubbles rise, then dumping the mix into a large quantity of alcohol (10 parts), stirring and allowing it to gestate for 5 minutes.   In the second method the water is not allowed to boil, any mixture attempting to dry along the sides of the container is carefully stirred back in to keep it moist and after the 5 minute dip in alcohol the excess fluids are strained and squeezed out through a cheese cloth.  In both methods the somewhat firm paste or cake is pressed through a screen to produce uniform granules.  The granules can be set on a tray or flat surface to dry out in the sun. The quicker it dries the more effective it will be (a role in which alcohol plays a part). One author advocated sprinkling in a little graphite (if available) at this stage; the granules swirled in a lidded plastic bowl like Tupperware® become rounded and uniform. 

The advance of chemical Explosives

There are some 800 uniquely identifiable explosive compounds but admittedly some of these are simply compounds of more basic explosives already on the list.  This post will end here but a follow-up or second part will explore some of the more noteworthy explosive compounds, including: nitrostarch, nitric acid, mercury fulminate, sliver fulminate, guncotton, nitrocellulose, nitroglycerin, dynamite, gelignite, ballistite, lead azide, cordite, picric acid (trinitriphenol or TNP), lyddite, TNT, significant mixtures of TNT with other agents, tetryl, PETN, semtex, DDNP, RDX or hexogen, HMX or octogen and CL-20





For about three million years prehistoric man apparently had no means to initiate a fire.  Once acquired from nature, maintaining a continuous fire then likely became a critically important function for someone – in a family, tribe or group.   It is assumed that humankind didn’t acquire reliable fire making skills until eons later, somewhere around 7,000 BC.  Then, as mentioned in a previous post it took humans about three thousand years to advance from copper – to iron – smelting temperatures; an increase of only about 500° Celsius.

*  Advancements in the control of fire’s concentration and the increase of its heat were critical prerequisites to tool improvement and therefore also crucial to our cultural evolution.   Anthropologist and archaeologist then are categorizing mankind’s cultural progressions into partitions  (i.e. Old Stone age, Neolithic age, Bronze age, Iron age, Dark age, etc.)  indirectly  based upon his ability to control heat.  

The process of initiating a fire would remain difficult and inconvenient for another 8,800 years.   Before the invention of the phosphorous friction match two short centuries ago, cultured society’s best fire starting technologies were scarcely improvements upon or less tedious to perform than those used by wild aborigine contemporaries or enlightened prehistoric cave men.   A review of some of these archaic techniques follows.

Starting from scratch 

Early on, the most popular fire starting method seems to have been the fire drill.  In this friction method the drill is a shaft of wood spun by hand pressure.  Dissimilar woods are primarily chosen, usually a harder wood for the shaft and softer one for the plank.  Continued friction causes powder or dust to separate from the softer wood and become heated.


In the image above a base plank is specially prepared with a notch to allow the tiny precious glowing ember of hot dust to fall out onto some tinder.  The person blows on the ember, creates a flame, and then adds more tinder and kindling – to make the flame grow.  The whole process appears easy enough, but in truth can be a significant chore.  With practice however an individual can make the process work in less than 60 seconds.  It’s a question experience, technique and good tinder.  The world’s record for getting a suitably hot coal with a hand-drill is 4.5 seconds.

Another ancient friction fire starting method is the wood plough.  Popular in Polynesian cultures, this method also requires careful selection of woods.  The base is usually a small tree trunk or staff of soft wood with a grove worn into it.  While the base is held immobile a plow of smaller diameter hardwood is draw back and fourth in the grove.  As with the fire drill, friction creates dust which turns into a hot ember, which is then dropped into some tinder.  Like the fire drill, the fire plow requires experience and steadily applied pressure to work.


A method of primitive fire starting popular in Indonesia is the “bamboo fire saw”.  A short section of dry bamboo is split in half.  On one half-section a small notch is started with a knife.  The other half-section that is to be used for the sawing can be whittled down in size and one edge should be sharp.  In method “A” below, the saw is below the tinder and is held still by the body pressing it against a firm object.  The ember is caught in the tinder above.  In method “B” below, the position of the saw is reversed and it is held in the hand.  The ember falls onto the tinder below.


A popular New Guinea variation of the bamboo fire saw utilizes a thin strand of bamboo or tough local vine as a rope saw.  The bamboo plank and tinder beneath are stood upon as the friction is applied.


The bow drill is actually an adaptation of the fire drill / hand drill method.  This method is also ancient.  Egyptians were using this method while building their pyramids.  Most other civilizations that used the bow for archery probably learned to use it as a fire starting tool also.  This was the favored method of some American Indian tribes although they did not forget about the hand drill.  An archery bow will work for fire starting, but a bow for such a chore does not need to be so big.  In fact a small branch about 2 feet long, with a small curvature, is optimum.


The same kind of bottom plank or fireboard  incorporated by the fire drill method is used.  Other acceptable fireboards are a pair of branches tied together, a branch that has a season split or a chunk of  dead and dried tree fungus


The shaft or spindle can be shorter with a bow drill (usually somewhere between 10” and 5”).  A thin spindle of about 5/8” to ½” diameter is probably best.  Initially pointed for starting a new hole, the spindle thereafter is kept round.  A socket of wood or bone knuckle is held in the hand that applies downward pressure in the spindle.  Optimally the spindle is braced under the shin, below the knee, where it can be held steady and secure.  Since the friction and heat is wanted only at the fireboard end of the shaft, the other end which held by hand will benefit from a socket with lubrication or a hard insert to reduce friction.  If the socket is wood then a metal bottle cap or a small concave stone insert will reduce friction while allowing more pressure to be gradually applied.  The types of wood used for spindle and fireboard make a big difference.   Given the choices at a random location – only experimentation will tell.  Yucca and Elm rate highly but Maple and Pine do not.


3 bow drill sockets

The Egyptian bow drill used several millennia ago was often a tiny affair.  One of its attributes was the fact that the spindle was attached to the string.  Extra coils of string were wrapped around the spindle (wrapped both directions from center).  This allowed better traction and control over the spindle.  The spindle was fastened either by the string passing through a hole in the spindle or by the tying of a simple clove hitch knot.  Someone skilled in its use can start a flame within 25 seconds, using a bow drill.  The world record in the late 1930’s for getting a flame with a bow drill was 7.5 seconds …


Another old variation of the bow drill is the pump drill.  The pump drill would be only slightly more complicated to build than the bow drill.  Used correctly, the spindle can be kept in continual motion by the centrifugal force or inertia of the flywheel and rhythmic motion of the pumping hand.  Useful friction would only be exerted on the downward stroke however.


Before the 19th century the most advanced means of initiating a fire was with a kit called a tinderboxThe tinderbox, typically made of metal usually contained a sharp piece of flint (rock), a hard piece of steel and tinder.   Tinder simply means some type of very combustible material.   Tinder can be anything from char cloth (linen or cotton cloth that has been pre-burned in a low oxygen environment) to spider webs, various plant fibers, termite dust, grass, pitch wood, bird’s nest, down, fungus, Spanish tree moss, paper from wasp or hornet’s nest, oakum, cotton balls dipped in Vaseline or lint taken from a clothes dryer.   Tinder needs to be dry, fibrous, fluffy, and highly ignitable.   Many materials can be masticated and crushed to make them more fibrous.   The fancier tinderboxes of the pre-match era often had a c-shaped or horse shoe shaped piece of metal to hold in one hand, while the flint rock was held in the other.   When struck together friction ignites tiny shavings of metal, not rock.


In all these afore mentioned fire starting techniques the precious spark or glowing ember must be captured by the tinder and skillfully assisted with extra oxygen to create a flame.

A more modern equivalent to the old flint and steel combination is the Ferrocerium rod.  Typically found in cigarette lighter “flints”, wind-up toys that spark or in a welder’s striker; ferrocerium is a man made mix of cerium and iron.  This material is usually pushed by a spring, against an abrasive piece of moving steel to create sparks.  As with the old flint and steel method, friction ignites tiny shavings of metal.  In this situation however the iron in ferrocerium burns, not the harder steel.  Cerium’s low temperature pyrophoricity is responsible for the easy sparking.  A modern survival kit might contain a single rod of ferrocerium as a fire starter.  It’s resilient to damage by water and reliable.  Better yet, a survival kit might include a magnesium fire starter.  Shavings of magnesium are scraped off into a little pile (already atop paper or other tinder).  The sparks are then scratched off the attached ferro-cerium rod, onto the magnesium flakes, which should then burst into flame.


* A little match history

It took humankind at least nine thousand years of trial & error, to progress from hand or bow drills, to fire starters as instantaneous as kitchen matches & butane cigarette lighters.  Yet we modern people causally dismiss matches and lighters as being very simple devices.

In 1669 Hamburg Germany, an alchemist was trying to convert some of “life’s essence” into gold.  He took some of his own urine, let it rot, then boiled it down to a paste, then cooked it some more—letting the vapors travel through water.  What he got was a waxy substance that glowed in the dark (ammonia sodium hydrogen phosphate).  Two years later the Irishman physicist Robert Boyle (Boyle’s Law) rubs this newfound phosphorus against some sulfur and creates a flame.  Boyle did not exploit his opportunity to invent the friction match.  Mankind was to wait another 1.5 centuries before finding an easier way to start a fire.

Along came an English apothecary and chemist in 1827.  He invents a functional but impractical match called the “Prometheus”.  This was a wood splinter with a potassium chlorate head placed next to a tiny glass bead of sulfuric acid, then rolled in paper.  A person used tweezers or a bite with the teeth to break the glass and set off the flame.  More importantly, our apothecary later sticks a mixture of starch, gum Arabic, antimony sulfide and potassium chlorate onto a stick and lets it dry.  This invention he calls a “Congreve”, named after an officer who had introduced War Rockets to the British arsenal.  Large rockets (16’ long) that could rise 9,000 feet in the sky and which sprouted great flames (some were used against Fort McHenry- Baltimore harbor, in the War of 1812).  Our English chemist and friction match inventor did sell a few matches but he did not get rich.  Another Englishman exploited the commercial market for these matches, and renamed them “Lucifer s”.  They became very popular with smokers, but stank.   In 1830 a French chemist created a match that did not stink, using white phosphorous which was highly reactive and toxic.

During the next 50 years large match factories were created that mostly exploited the cheap labor of children, young girls and women.  “Phossy Jaw” was a famous ailment caused by inhalation of white and yellow phosphorus vapors in the match factories and often led to death.  The English “Suffragette Movement” and a defining moment in trade union history started with women striking against conditions and hazards of the match factories, in the Bow district of London.

In 1855 a Swede created the first safety match, using less dangerous red phosphorus and ignitable only on the box.  In 1889 the first matchbook matches were invented and were called “flexibles”.

By 1910 the Diamond Match Co. patented the first nonpoisonous match, using sequisulfide of phosphorous.  Asked by President Taft to release their patent for the good of mankind, Diamond Match did in 1911.   A century later the once common strike anywhere type of kitchen match has become rare in the US today.


More modern “primitive” fire starting methods

Everyone probably knows that by using a magnifying glass, energy from sunlight can be concentrated enough to start a fire.  Without a quality lens and the cooperation of good sunlight thought, even this task is easier said than done.

A ray of light passing through the center of a thin lens keeps its original direction.  A ray that strikes anywhere else is bent. The amount a light ray is bent increases with its distance from the center of the lens.  A magnifying glass is actually a double-convex lens.  It can gather the energy from a broad area and concentrate it into a smaller area.  The focal point or hot spot is where parallel light rays converge (cross) along the principle axis of the lens.


Dust and scratches or imperfections of the lens will diffract the light and lessen the practicality of this fire starting method.   Plastic or toy magnifying lenses generally diffract, diffuse, disperse or scatter so much light that they are useless for starting flames.  One is not likely to have or to run across a magnifying lens in an emergency situation.  Other types of lenses might be available however, and might be drafted into making an improvised double-convex lens.   Glass lenses can be salvaged from eyewear, cameras, binoculars, and telescopes.  The first two lens shape a & b in the following image, bends light in a way that’s unbeneficial to fire starting.  A pair of lenses with the shape a, back to back however might adequately mimic a double-convex lens.  The last two lens shapes e & f are the type normally found in eyeglasses.


A drop of water placed on the back or inside of lens type e or f, will produce a temporary double-convex shape.  The surface tension of the water droplet should produce the opposing convex surface.  It takes a very steady hand to find the optimum focal point and to hold eyewear and water still; long enough to initiate a flame.  Not all eyewear is created equal so the vision prescription will actually be a factor in any success.


Another clever idea for making a fire in an emergency involves the simple clear plastic sandwich “baggie.  One fills the baggie with water, and then twists the contents into a bubble or sphere.  With this makeshift double convex lens, one again needs to focus the hot point upon the tinder and hold it steady, long enough for the sun to do its work.  A clear chunk of ice might also concentrate solar energy in one spot, long enough to ignite some tinder.   The notion however, of starting a fire with anything less than a very good lens is nifty but frequently impractical.   Keeping the water from leaking can be difficult as is holding it still for any duration.   Even when sunlight is strong and direct an average lens will diffuse the light so much that even the driest tinder will not ignite.  This water baggie idea is more fanciful than realistic.


A parabolic mirror or highly polished parabolic surface can also capture heat from the sun.   If held at the correct angle to the sun, the surface will concentrate the light into one small spot along the edge of the parabola.  For example a person could polish the concave bottom of a beer or soda can to a high sheen, using some steel wool.  If steel wool cannot be acquired, perhaps diataneous silica, abrasive leaves from plants in salt marshes or graphite (as in a pencil lead) might work.  Graphite is commonly used as a lubricant but it can also perform as a mild abrasive.  The polished surface (bottom of can) is then propped up by rocks and pebbles until the sun is caught at a very small spot at the bottom edge of the can.  Very small pieces of tinder are then dropped onto the hot spot and should become hot enough to ignite.


Flashlight batteries & steel wool are a handy way to start a fire.  For many decades Boy Scout manuals have advocated this trick.  One strips a small ribbon of wool to the proper length to reach both positive and negative terminals, and then shorts it out.    Two 1.5 volt cells in series provide 3 volts, which is usually enough energy to make the steel wool glow red hot and then ignite.  Larger batteries will work also.


Another interesting fire starting method is the ingenious “fire piston”.  This device was discovered by Europeans visiting Indonesia in the 1860’s.  (* Indonesia incorporates Sumatra, Indo China, the Philippines, Borneo and about 17,508 islands in between).   The fire piston is thought to be an ancient device because of its wide distribution.  It may have resulted from the development of the blow gun or blow tube.  The fire piston works on the same principle as the Diesel engine.  A hand sized tube is fitted with a close fitting rod (piston).  For a tight seal the rod is fitted with a gasket of string or sinew and packed with animal fat or wax.  A small piece of tinder is placed in the dimple of the plunger, the plunger inserted into the tube, and a pump or two of the piston generates enough heat (through pressure) to ignite the tinder.  The fire piston requires careful construction and close tolerances, but it is apparently a very reliable device.


Yet another interesting proposal is that of using ammunition from a firearm to build a fire.  The notion of dumping ½ of the gunpowder from a cartridge out and stuffing in a bit of rag cloth to replace the bullet is suggested.   Ideally the propelled cloth should smolder long enough to ignite tinder (and excess gunpowder).  In practice however the cartridge primer usually just ejects the cloth and fails to ignite anything.  The process might work for someone under special conditions with the right firearm using a cartridge with the right powder.  Pistol cartridges use the fastest, most volatile nitrocellulose powders.  Shotgun powders use the equivalent of slower pistol powders.  Rifle powders use the largest grained, slowest burning powders of all; and therefore should be the hardest to ignite.  Firecracker or ‘flash’ power is faster than black powder and both deflagrate faster than nitrocellulose powders.  In any event, gunpowder from any firearm cartridge would compliment other tinder or help start a fire from an ember achieved by other means.  Gunpowder can be unpredictable or sometimes troublesome to ignite.   Many a fool has probably blackened his face or singed his eyebrows by patently holding a flame to the stuff.



In conclusion it is hoped that the reader will part with a few new notions.   Throughout history, fire and its heat have played an extremely significant role in the development of human technology and culture.  Refined heat allows us to create sophisticated materials, it extends our lives by allowing us to survive cold weather, it generates our electrical power and kills disease in our food before we eat it.  The reader should now be better equipped to initiate a fire in an emergency, possibly using one of several different archaic methods if absolutely necessary.   If unpracticed in these primitive skills however, he or she might soon discover that what looks so simple can actually be very difficult.xlighter4

* Bit of trivia:

It may not be appropriate to call someone a good Boy Scout just because they can start a fire.  

– The Boy Scout movement began 1908 in British Isles, and spread to America by 1910.  The society attracted urbanite boys and instructors more than countrified counterparts.  For a century now, the thirteen different editions of the Boy Scout handbook have traditionally placed more emphasis on controlling fire rather than starting it.  Never has skill in fire making been a requirement for scout advancement.  In 1911 the only fire related merit badge was for Firemanship, which focused upon extinguishing fires safely and avoiding panic. Today’s equivalent merit badge for Fire Safety differs slightly by including small requirements like that of igniting a camp stove prudently. 

– Where modern Scout manuals might have more images and information concerned with outdoor skills, yesteryear’s handbooks were more moralistically toned for building leadership, character and integrity.  When examining some of the older editions it would appear that people had a more defined set of ethics than they do today.  



Familiar Batteries



Although at first they may appear to be mundane topics for discussion, batteries are contributing in ever increasingly important ways to the modern lifestyle.   Items from spacecraft to even some failing human hearts depend upon batteries.    Although a myriad of battery types and chemistries exist, none are ideal or are very long lasting.   In almost every category the quest for a better battery solution, is an urgent one.   Here in this post an attempt is made to illuminate the construction, advantages or limitations, recycle-ability and where applicable the proper recharging of some of the most common consumer grade batteries.


The “dry cell” battery made its first appearance during the Paris 1900 World’s Fair.    From this evolved the zinc-carbon cells which were so ubiquitous during the 1960’s.   Such cells are not dry, but actually contain an electrolyte of moist paste.   So-called “heavy duty” (zinc-chlorine) cells began to appear which offered an improvement in performance by featuring purer chemicals and an electrolyte of zinc chloride.   In today’s marketplace zinc-carbon and zinc-chloride cells have been largely displaced by the more expensive alkaline cell.   So far, all of these cell types are progressive variations of the original Leclancé cell invented around 1866.  In some circles zinc-carbon cells are simply referred to as Leclancé cells.

Leclancé cell image modified from public domain source

The term “primary cell” denotes a battery which is intended to be thrown away and not recharged after use, while the term “secondary cell” denotes a rechargeable type.   Battery chargers for zinc-carbon and zinc-chloride batteries have been built in the past but their effectiveness was minimal and the process fairly pointless.  The components of these old style cells contain materials however which might be useful to an experimenter.   For example the cases of Leclancé type primary cells are made of useful zinc.  The carbon graphite rod at the cell’s center can be filed to a point at one end and when attached to a 12v automotive battery, can be used to expeditiously solder electrical connections in an emergency.


Furthermore both zinc-carbon and alkaline cells contain manganese oxide (specifically manganese (IV) oxide) ; a common inorganic pigment used in dyes, paints, ceramics and in glassmaking.   As long as 19,000 years ago in Europe prehistoric cavemen were painting cave walls black and dark brown with manganese oxide and were achieving umber, sienna & burnt sienna hues by mixing or cooking in with this, varying amounts of iron oxide.    Ammonium chloride (NH4Cl) composing the electrolyte of the zinc-carbon cell is made by the reaction of hydrochloric acid and ammonia.  This chemical has a wide range of applications.   Also known as Sal ammoniac, ammonium chloride can be found in food additives, baked bread where it acted as a yeast nutrient, salty licorice candy, cattle feed and in some cough medicines where it acts as an expectorant.   Ammonium chloride acts as a nitrogen source in some fertilizers, it can be found in the glue that bonds plywood and as a thickening agent in certain hair shampoos.   Ammonium chloride can clean a soldering iron.   It is used in some soldering fluxes and once upon a time in the past it was even used (along with the help of a little copper) to produce green and blue colors in fireworks.   Zinc chloride (in Heavy Duty cells) can also be found in non electrical, corrosive soldering fluxes.  Sometimes used as a disinfectant, in antiseptic mouthwashes and dental fillings, zinc chloride of higher concentrations can also dissolve cellulose, starch and silk.  Zinc chloride is also a frequent ingredient in military smoke grenades.


In a battery, energy density is the amount of energy stored in a given space per unit volume or mass.  Alkaline battery cells have 3-4 times the energy density and a much improved shelf life compared to a zinc-carbon cell.  Appearing on the market in the late 1960’s, these usually have an outer shell made of steel.  Although generally thought of as primary batteries and contrary to what might be stated on a label, alkaline cells can be recharged.  A small current at about 65mA, interrupted periodically will do the trick.  Commercial pulse chargers for alkaline cells are available but rare.   Alkaline cells get their name from the strong base of potassium hydroxide (caustic potash) used in the electrolyte.   Potassium hydroxide (KOH) is hygroscopic (with a high affinity for water) and is sometimes used as a desiccant.   Some shaving creams, cuticle removers and leather tanning solutions to remove hair from animal hides – employ potassium hydroxide.

The 9 volt battery is properly termed a ‘battery’ because it is composed of a bank of individual 1.5 volt cells.  The construction of the 9 volt battery has varied over the years but nowadays the most common assembly is of 6, rarely seen AAAA type cells.

Some other less common primary dry cells that won’t be discussed here include: the aluminum battery, chromic acid cell, nickel oxyhydroxide battery, silver-oxide battery, and zinc air batteries.  Again, the main difference between a primary battery and a secondary battery is the ease with which the chemical reaction within the cell can be reversed.   “A battery charger functions by passing a current through the cell in a direction opposite to that of the flow of electricity during discharge.”


It may be useful at this point to realize that the spiral wound (Jelly-roll or Swiss-roll) construction of some of the next battery cells to be mentioned and the construction of some capacitors can appear to be similar.  Over time in spiral wound batteries and capacitors alike, crystalline structure in the plate material or electrolyte eventually changes and causes complications.   Also the separators that isolate plates can deteriorate with age, eventually allowing opposing plates to make contact and short out.  When old devices like radios, stereos and TV’s stop working it is often discovered that bad capacitors caused the problem.   Simpler than a battery cell, a capacitor doesn’t produce electrons – it only stores them.  A capacitor can dump its entire charge in a split second whereas a battery cell discharges much more slowly.


Nickel–cadmium batteries (NiCd or NiCad) got their name from the chemical symbols of their electrodes.   The first NiCD battery was a wet cell created in Sweden around 1899.   Beneficial attributes of this type of rechargeable battery include its tolerance to being deeply discharged for long periods, the fact that it can withstand very high discharge rates with virtually no loss of capacity, its lower self-discharge rate, and its performance in cold weather.  Outdoor solar patio lamps are one application where NiCds work admirably.   Negative attributes of the NiCd type would include a phenomenon known as voltage depression (voltage depletion, “lazy battery” or “memory” effect).   Voltage depression in this case is attributable to increased internal resistance caused by metallic crystal growth in the cadmium.   Improper or unsophisticated recharging of NiCads is probably the main reason for the continuing decline of their popularity.  The surface of the cadmium plate in a good NiCD cell has a small crystalline structure.  When these crystals begin to grow then the surface area is reduced so voltage depression and loss of capacity result.  The crystals can grow large enough and sharp enough to penetrate the separator between electrodes.

* It is sometimes possible to temporarily reclaim “spent” NiCD cells or battery packs with a trick.  By zapping NiCd cells or battery packs with a strong DC current like that from a welder or automotive battery charger (where positive to positive and negative to negative terminals meet) the size and sharpness of the crystalline dendrites within the cadmium hydroxide electrode can be reduced and performance partially restored.   Even battery packs that seem to have been dead for several years can be recovered this way.  If not used constantly however these seem to return to their original dormant state much sooner than they should.  Nickel based cells have venting mechanisms to allow gasses to escape in the event of heat from overcharging.  Therefore the electrolyte might dry up.  As with other “dry cells” the electrolyte can migrate away from the terminals over time also.

There is not much that can be reclaimed from either a NiCd or NiMH cell.   Cadmium hydroxide is more basic than zinc hydroxide.   Cadmium (Cd / atomic # 48) is a rare, soft, ductile and toxic transition metal that is found in trace amounts in most zinc ores and is often collected as a byproduct of zinc production.  Sometimes replacing zinc for corrosion resistant coatings, cadmium electroplating of steel is common with aircraft parts.  Cadmium can be found in nuclear reactors where it controls neutrons in nuclear fission.   Red, orange and yellow paint and plastic pigments are often made with cadmium.

NiMH cells (Nickel-Metal Hydride) are similar to NiCd cells, having replaced the negative cadmium electrode with one of a hydrogen absorbing alloy.   Superior in some ways but not in others to NiCads, NiMH cells only arrived in the marketplace in 1989.   Having 2-3 times the capacity of a NiCd cell they are useful in high drain applications like the demands from digital cameras as an example.   NiMH cells however have a very high self-discharge rate (perhaps 30% a month).  That means that they lose their charge just by doing nothing.   NiMH cells exhibit much less apparent voltage depression or recharge “memory” than NiCd types but it can still occur.  Unlike NiCd cells, NiMH cells should not be deeply discharged (except upon occasion before recharging) and they should be kept “toped up” or recharged frequently.

 * The amount of energy expended by a typical “AA” alkaline battery is about 5,000 C (Coulombs -> 1C = about 6,241,000,000,000,000,000 electrons).  Rechargeable “AA’s” and some alkalines display the relative capacitance of a cell with a “mAh” (Milliamp hour) rating.  One mAh = 3.6 C and 1,000 mAh’s = 1 Amp hour = 3,600 C.  Often compared to the gas tank of a car, the voltage represents how much gas is being used while the mAh represents the size of the gas tank.  A car with a bigger gas tank will go farther but the bigger gas tank will also take longer to refill.    

*  The mAh rating stamped on an “AA” battery can be misleading if comparing different types of batteries.  New alkaline “AA’s” might have a 2,500 mAh rating, while rechargeable  NiCd’s or NiMH’s might only be rated at 1,200, 1,900, etc.  In high-drain applications (like digital cameras) however these rechargeable cells will far outlast the alkaline types even before being in need of a recharge.  Alkaline batteries are not designed for high discharge demands, and only deliver full capacity if the power is used slowly.    


* Some of the first “button” type battery cells were mercury or mercuric oxide batteries.  Used in hearing aids, watches, calculators and other small portable electronic devices mercury cells were popular and common between 1942 and the early 1990’s.  In the 1990’s the European Union and the United States began to legislate this type of chemistry out of existence.  Mercury cells had a 1.35 nominal voltage and high capacity, achieved from using an alkali electrolyte with zinc and mercuric oxide electrodes.

Cells in the Lithium battery family use lithium metal or lithium compounds in the anode but vary widely in choice of cathode and electrolyte.  Lithium cells offer higher voltage and larger energy density than most other battery types but they are also far more expensive.    Depending on its chemistry a lithium cell can provide 3.3 – 3.7v of nominal cell voltage (compared to: 1.5v for zinc carbon, zinc chloride and alkaline cells, or 1.2v for NiCd and NiMH cells).


Lithium Prismatic cells of monopolar or stacked configuration are similar to the voltaic pile in concept – with the positive and negative plates are sandwiched together in layers with separators between them.   A new way to construct multiple electrode cells is to arrange them in what is called a “bipolar configuration”.   This looks like a stacked sandwich or prismatic configuration but here the negative plate of one cell becomes the positive plate of the next cell.   Almost a play upon words is the term “bipolar” because of the historic use of this unusual metal in treating manic depression (more commonly referred to today as “bipolar disorder”).   More on this bipolar topic momentarily.

Because they are pressurized and may use a flammable electrolyte “Lithium-ion” batteries can be dangerous.   A standard lithium cell is not rechargeable but a lithium-ion cell is.  While lithium primary cells have electrodes (generally anodes) of metallic lithium, rechargeable lithium-ion battery (LIB or Li-ion battery) cells use electrodes composed of various materials impregnated with lithium ions.   [Some examples are: lithium iron phosphate (LFP), lithium cobalt oxide (LiCoO2), lithium nickel manganese cobalt oxide (NMC)and lithium manganese oxide (LMO)].   Some of the newest battery designs being contemplated by researchers are impregnating carbon nanotube cathodes with lithium on a nanoscopic scale (particles usually measuring between 1 and 100 nanometers).  In the near future we may witness the commercialization of the so-called “nanobattery”.

The capacity of Li-ion type rechargeable batteries will diminish substantially after a few years.   Li-ion cells don’t have a “memory” and don’t get confused by shallow discharges.   It is not wise to strain such a battery by frequently discharging it completely, nor is it beneficial to keep it fully charged all the time.   Quick discharges also place strain on this battery type.  Over time a regularly used Li-ion battery will suffer less capacity loss than one that is used infrequently.   These cells don’t like extreme cold but they hate hot temperatures.

Popular lithium-ion polymer batteries (LiPo, LIP) should connote cells built with a non liquid polymer electrolyte that does not leak.   Confusing the issue however, manufacturers soon expanded this meaning to include lithium cells with pouch type flexible polymer casings.

* Lithium is a very curious material.  It does not occur naturally in a pure state because it is a highly reactive alkali metal with one of the highest reduction potentials of any element.  With an atomic number of only 3, refined lithium metal would be so soft in could be cut with a knife and so light that it would float on water.  A comparatively rare element and strategically important material, it is hard to acquire and therefore costly.   The price of the metal has sky-rocked since WWII.  During that war lithium was mainly used as Hi-temp grease for aircraft engines.  Soon later it was used to stage man’s 1st nuclear fusion reaction (1952 / lithium transmutation to tritium).  In 1954 when mixed with hydrogen (as lithium deuteride) it composed the fuel of the Bikini Atoll (Marshal Islands / Castle Bravo) thermonuclear “H” bomb.  This particular test surprised its designers by being a far more powerful blast than expected (@ 15MT the greatest yield of any U.S. nuclear test) and also created international repercussions concerning atmospheric thermonuclear testing.  Low concentration but stable lithium hydroxide was stockpiled for many years due to its strategic value in the manufacture of hydrogen bombs.  In nuclear power plants or ship/submarine reactors lithium might be employed as a coolant by moderating boric acid in the absorption of neutrons.   In some underwater torpedoes a block of lithium might be sprayed with sulfur hexafluoride to produce the steam which cranks the propeller.  Lithium is used in heat-resistant glass and the manufacture of telescope lenses because lithium fluoride crystals have a very low refractive index.  Chosen for their resonance, lithium niobate crystals are used in mobile phones.  Lithium is used as an oxidant in red flares & red fireworks, as a flux for welding and soldering and as a fusing flux for enamels and ceramic glazes because it lowers their melting points. 

Sodium affects excitation or mania in the human brain so doctors and psychiatrist might often issue lithium as a mood stabilizer.  For treatment of bipolar disorder / manic depressive disorder, lithium affects the flow of sodium through nerve and muscle cells in the body.   The terms for this disorder denote uncontrolled mood swings from up to down or high to low and back.   Lithium treats the aggressive, hyperactive and manic symptoms of the disorder.   In humans amphetamines produce effects similar to the symptoms of mania and herein lay another interesting quality of lithium.   Apparently lithium battery cells (a cheap source of the metal) are frequently used as a reducing agent in the illicit manufacture of methamphetamine.  One recipe called the “Nazi method” requires anhydrous ammonia, ether, lithium and pseudoephedrine.  A more complicated recipe also uses lithium but substitutes anhydrous ammonia with ammonium nitrate, lye, salt and a caustic drain opener composed of sulfuric acid and a cationic acid inhibitor.  Double methylated phenylethylamine (Meth) and its precursor amphetamine are both built upon the plant derived alkaloids ephedrine and pseudoephedrine.   Ephedrine and pseudoephedrine (from the Ephedra distachya plant) are active ingredients found in several brands of effective antihistamine.

The largest producers of lithium are Chile and Argentina.  Large deposits of lithium have been discovered on the Bolivian side of the Andes and there is a lot of the metal dissolved in the oceans.  Acquired primarily from brine lakes, clays and salt pans where it is refined electrolytically, production of the metal is slow.  There is no standard spot price for the metal in a futures market or stock exchange.  China has become the world’s largest producer and consumer of lithium ion batteries.   Presently ever-growing in utility and popularity and expecting huge requirements of this metal in future electrical automobiles, market analysts predict that production of lithium will soon fall short of fulfilling its demand.


The construction of lead-acid automobile batteries has changed very little in the last 50-60 years.   A standard car battery has a conventional voltage of 12.6 volts achieved with only 6 cells, because the nominal voltage of each cell is 2.1 volts.   Typically in each cell alternating plates of different polarity {+ containing lead dioxide (PbO2) and (-) of plain lead (Pb)} are separated by nonconductive paper or synthetic dividers and surrounded by an electrolyte of about 35% sulfuric acid (H2SO4) and 65% water.  The electrolyte of a healthy cell should have a specific gravity of 1.265 @ 80°F.

*   During the discharge cycle of a lead-acid battery; the negative plates (lead) combine with the SO4 (of the sulfuric acid- H2SO4) to produce lead sulfate (PbSO4) and the electrolyte’s specific gravity goes down.   The electrolyte becomes weaker and the potential between ± plates diminishes.   Conversely, during the charge cycle electricity is passed through the plates forcing SO4 back into the electrolyte.   The lead sulfate is broken up as lead oxide and plain lead are re-deposited upon their respective plates.   The specific gravity and voltage (potential between plates) are re-elevated to the proper levels.

Industry nomenclature- lead acid batteries

Aside from common automotive batteries, buyers also have access to “maintenance free” batteries, “deep cycle” batteries, “hybrid” or “marine” batteries, “gelled” deep cycle batteries and “AGM”(Absorbed Glass Mat) batteries.   The chemistry of these differing lead-acid batteries remains the same but the quality or quantity of the components change.  “Maintenance free” batteries are usually just heavy duty versions of the same basic design.   Generally the construction is better, components are thicker and the materials are more durable.   Commonly the plate grids contain cadmium, strontium or calcium to help reduce water loss by reducing gas.   Such batteries are often closed systems (can’t add water or check specific gravity) and they are often referred to as “lead-calcium” batteries.

Automotive batteries are optimized to start car engines.  The hardest work they are expected to do is to start a cold engine on a cold day.  Hence they are constructed internally with many thin plates within each cell, to maximize surface area and therefore current output.  An automotive battery is designed to produce a large current for a short time.  Unless abused, a car battery is seldom drained to less than 20% of its total capacity.  Allowing this type of battery to drain beyond that point (or allowing it to self-discharge by not using it for long periods) can be very detrimental to the battery’s longevity.   By contrast “deep cycle” batteries as used in golf carts, electric fork-lifts and for boat trolling motors are optimized to provide a steady amount of current for a protracted period of time.  These can be deeply discharged (80% of capacity –although doing so strains the battery), repeatedly whereas an automotive battery cannot be.   Deep cycle batteries have fewer plates but thicker ones within each galvanic cell.  The plates have higher density plate material.  Less electrolyte and better separators are also used.  Alloys used for the deep cycle cell plates may incorporate more antimony than car batteries do.

* Lead acid batteries generally have two common ratings stamped upon them; CCA & RC.   Cold Cranking Amps (CCA) is the number of amps a battery can produce –for 30 seconds @ freezing temperature (32°F or 0°C).    Reserve Capacity (RC) is the number of minutes that a battery can deliver 25 amps at or above a 10.5 volt threshold.

Generally, a deep cycle battery will possess only one half to three quarters the cold cranking amps but twice to three times the reserve capacity that an automobile battery will contain.  A deep cycle battery can endure several hundred total (complete) discharge/recharge cycles whereas a car battery is simply not designed to be totally discharged.  This reserve capacity and discharge tolerance makes deep cycle batteries preferable to automotive types for the purpose of off-grid electrical storage purposes.  Any lead acid battery however will last longer if it is not allowed to discharge to a great degree.  A battery discharged to 50% every day will last about twice as long as one cycled to 80% of capacity daily.  For less strain and increased longevity, deep cycle batteries should probably be drained no more than 10% on a daily basis.

Hybrid” batteries or “Marine” batteries may be labeled deep cycle, but are something of an undesirable compromise.  “Gelled” deep cycle batteries offer a safer, less hazardous electrolyte in gel form but at a heftily increased price.  AGM (Absorbed Glass Mat) batteries incorporate a Boron-Silicate glass mat between plates.   Also called “starved electrolyte” batteries, the mats are partially soaked in acid.  These are less hazardous because they won’t spill or leak acid if damaged.  These sealed batteries also recombine oxygen and hydrogen back into water during charging.  The lifecycle of an AGM deep cycle battery typically ranges between 4 to 7 years.  Deep cycle Gelled and AGM type batteries can get pretty big and might cost well over $1,000 each when new.

All lead-acid automotive and deep cycle type batteries will eventually age or fail, but for a wide variety of reasons.  A normal automotive battery might age because lead dioxide flakes off the positive plate due to natural contraction and expansion during everyday discharge and charge cycles.  Shorts between plates, buckling of plates, loss of water, negative grid shrinkage, positive grid growth and positive grid metal corrosion can cause a battery to fail.  Battery aging can be accelerated by fast charging, overcharging, deep discharging, high heat and excessive vibration.  Acid stratification is a situation where weak acid is at the top and concentrated acid at the bottom of an automotive battery, and is a condition caused perhaps by a power hungry car that is not driven enough to fully charge its battery.  Sulfation is also caused by undercharging or by allowing a lead-acid battery to self discharge by sitting for a long period in an undercharged condition.   In a sulfated battery hard lead sulfate crystals will fill the pours and coat the plates.  In a few instances it may be possible to rectify sulfation in a battery but beware of false claims and salesmen selling snake oil.

* It is interesting to note that a lead-acid battery does not require sulfuric acid as an electrolyte, to work.   Alum (hydrated potassium aluminium sulfate) solutions work and alkali or base solutions may work as well.  An evident superiority of sulfuric acid is that it works as antifreeze by causing a significant freezing-point depression of water.   Alum solutions tend to crystallize as well as freeze.

Methanol fuel cell / NASA image

Methanol fuel cell / NASA image

Fuel cells

Fuel cells are similar to batteries in that they convert chemical energy into electricity.  Like battery cells, fuel cells have anodes, cathodes and electrolytes.  The main difference between the two is that the chemicals are self contained within a battery’s cell(s) but must be imported or fed to a fuel cell.  A continual supply of fuel and of oxygen or another oxidizing agent must be fed or input to the fuel cell to perpetuate its chemical reaction and electrical output.   Methanol, natural gas or hydrogen perhaps from these are the most commonly used fuel cell fuels.

Although “fuel cell technology” may seem like new buzzwords in the automotive industry an Allis-Chambers tractor was driving around under fuel cell power more than half a century ago.   A Welshman invented the first fuel cell in 1839 and below is one of his sketches.


Of the several types of fuel cells designed thus far the electrolyte (whether it be liquid or solid) chosen determines the composition of the anode, cathode and usually a catalyst as well.   Alkali fuel cells use an electrolyte of potassium hydroxide, operate around 350° F and require an expensive platinum catalyst to improve the ion exchange.   A  Proton Exchange Membrane fuel cell uses a permeable sheet of polymer as its electrolyte, works around 175° F and also requires a platinum catalyst.   Platinum catalysts are also required for Phosphoric Acid fuel cells, which use corrosive phosphoric acid as the electrolyte and work at about 350° F.   High temperature salts or carbonates of sodium or magnesium are generally the electrolyte of choice in Molten Carbonate fuel cells.  These fuel cells work at a hot 1,200° F perhaps and employ a non-precious metal like nickel as the catalyst at both electrodes.   Hotter yet, Solid Oxide fuel cells require an operating temperature of about 1,800° F before the chemical reactions begin to work.  The electrolyte in one of these cells is frequently a hard ceramic compound of zirconium oxide and the catalytic activity is enhanced by the complicated composition of its electrodes.


Homemade Batteries

In a previous post Luigi Galvani, Alessandro Volta, the voltaic pile and Benjamin Franklin’s coinage of the term “battery” were discussed.   The image above shows several ways to construct simplistic batteries.  Each of these examples exploit dissimilar metals and an electrolyte that can be either acid or alkali based.


In the image above a potential and usable current should be created once an electrolyte is poured into the can, except for one problem.  Beer and soda cans are spayed with a plastic polymer coating to prevent interaction of the beverage with the metal, and this coating would interfere with ion exchange.  In a battery cell the current carrying capacity (or power) is governed by the area of the electrodes, the capacity is governed by the weight of the active chemicals and the cell voltage is controlled by the cell chemistry.  While a strong electrolyte might produce more voltage it would also eat through the very thin wall of the aluminum can sooner.


The notion intended by the image above is that a PVC pipe holds an electrolyte (preferably a mild mixture of bleach and water) and electrodes of copper pipe and tin solder are used.  Obviously the anode and cathode must not make contact but the closer they are suspended together- the better the ion exchange will be.   House wiring (just called “Romex” by some American electricians) comes in both copper and aluminum versions and could also be applied in this fashion.


To prevent sacrificial damage of the electrodes when this type of primary is not being used, it would be beneficial to be able to remove the electrolyte.  This image above suggests a way to connect PVC pipe together so that electrolyte could be added or removed when necessary.   Eight cells would produce 12v if their nominal voltage was 1.5 volts each.


The antique Daniell cell (above) probably could have gone without mention here except that some artistic types might find it interesting.  Looking to eliminate hydrogen bubbles, Daniell (1836) came up with a battery cell that used two electrolytes rather than one.   Originally, solutions of copper sulfate (deep blue in color) and of zinc sulfate (or sulfuric acid) were separated by a porous barrier of unglazed ceramic (or plaster of Paris, later used by Bird).  Operation of a single cell (2 half cells) worked fine until the porous barrier became clogged up with deposited copper.   Later a ceramic pot inserted inside a copper jar separated the two solutions.  Because of the flow of current the ceramic eventually became coated with copper.  Even later variations of the Daniell cell included the Bird’s cell and the gravity or crow’s foot cell.  In the gravity cell the difference in specific gravity of the two solutions is all that is necessary to keep them separated.  The containers of such cells should not be jostled.  Gravity cells were the favored source of power for telegraph stations especially in remote areas, for about 90 years.  Their zinc electrode resembled a crow’s foot, the batteries were easily maintained by replacing simple components – as needed.   Modern incarnations of the Daniell cell incorporate a “salt bridge” (either a glass tube filled with a fairly inert jellified solution of potassium or sodium chloride, or filter paper soaked in the same two chlorides).  When breaching two separate containers, the salt bridge completes the circuit – allowing only ions to flow back to the anode.