The History of Leather Tanning
How small human communities went from preserving hides in the wild, to tanning leather as a crucial link of civilization.
Human beings aren't known for having a lot of natural physical advantages; we are hairless, bipedal apes with big exposed fronts, eyes that point forward, and we are more or less without any natural weapons or defenses. By any purely physical description, we sound like walking infants. But Human beings are tougher than that, and smarter. In pre-history, ancient humans were faced with life or death environments in which survival was a matter of the intelligent use of resources. For many early homo sapiens, this was the shield that served us better than any natural defense ever could.
Prehistoric Hide Tanning
It’s not clear when people first began to wear clothes; the use of clothes is closely linked psychologically to our sense of vulnerability, to our sense of self-consciousness.
Protection against the cold was a massive advantage in more northern climates. When our ancestors first arrived in these climates, they were forced to adapt their technology to the environment; a better short term solution than waiting for natural selection to force you to grow fur again. Sewing together fur hides and wearing them as cloaks provided a little cover for the first humans who braved the harsh winters. Archaeological evidence as far back as the Paleolithic (around 400,000 years ago), shows that there were stone tools being created and used for the purpose of scraping the fat and flesh from hides. Primitive awls meant for piercing holes have been found, as well as holed needles for sewing furs together.
But all this is a far cry from actual leather; human beings would have had to figure out a way to preserve their hides from the elements too. A skin taken directly off an animal and worn will either rot, or dry out and become stiff. This is where we get the modern product of rawhide; a fully dried out piece of animal skin that has been de-haired and fleshed but otherwise untreated. While useful in many capacities, good clothing it does not make. Any untreated skin our ancestors wore might have lasted them a little while, before drying out and turning into a rigid and inflexible rawhide.
Being pioneers in the clothing business, early entrepreneurial humans would probably have developed ways to preserve their hides either by experimentation or accident. Weirdly enough, other parts of a hunted animal are sometimes highly suitable for preserving the skin. Brains, bone marrow, and many types of animal fats can be used to soften and preserve the hide.
This may have looked very similar to the methods used by modern Native Americans who preserve their hides using a traditional method known as “brain tanning”; a process that creates incredibly soft and vibrant leathers that are still cherished to this day.
After having skinned the animal and removed the hair, tanners would either soak the skin in a brain solution, or the brains were made into a paste and worked in carefully. Other organs such as the spinal fluid, bone marrow, and fat could be used to soften the hide. Smoking the skins over a smoldering campfire could help to soften them further. Using these ancient techniques, its possible that - even before the advent of animal husbandry and agriculture - humans had highly refined the preservation process.
Early Leather Tanning in Civilization
As agriculturally minded people began to settle along rivers and coasts to farm, they also began to gather herds of livestock. This gradual trend towards civilization saw a whole new era of leather tanning and leather use among human groups.
It’s more than likely that for a time people treated their hides in the same way as they had before, with little improvements over time. Early villagers would have portioned off an area specifically for hide working; creating open air pits for soaking hides, as well as wooden frames exposed to the sun for stretching and drying; perhaps the forerunner to the tanneries that would come later.
But as access to resources changed and new opportunities presented themselves, settled peoples would begin to change the way they tanned their leather and would begin to experiment with new methods.
Alum Tawed Leather
Early in history we find the first evidence for Leather “tawing” or the use of alum and aluminium salts to preserve hides. There are references in many different cultures, from Ancient Egypt to China and India, for the mining and use of alum.
Aluminium salt was mined on a large scale in early civilizations, to be used as a fix to dye fabric, for glazing ceramics, in medicine as well as cosmetics. But Alum could also help to preserve animal skins from rot and drying. After being soaked in a solution of Alum, the hides had to be greased with fat to prevent them becoming stiff, but the result was a soft white leather that would keep in hot climates and would accept dyes easily. Alum allowed some communities to produce unique leather, but the tawed leather was water sensitive and the tannins could be washed out; the hide was not “truly” tanned.
Oil and Fat Tanned Leathers
An extension of earlier methods of hide preservation using animal by-products, Oil tannage was expanded upon when new resources came into play. As their hunter gatherer ancestors had done, civilized peoples used animal fats and organs to dress their leather hides, allowing the oils to oxidize into the skins to preserve them.
In different parts of the world where local resources varied, Oil tanning could include all kinds of strange ingredients. Central Asian Nomads were known for using milk and butter from cows, egg yolk tanning was practiced by peoples of northern China as well as smoke curing in large pits. In North America then as today, brain and oil tanning was practiced as well as the smoking of the hides. In different coastal communities across the world from North America to China and Japan, fish leather was being used to supplement other kinds of clothing and was easily accessible. Fish oils could be used for tanning many different varieties of animal skin.
Vegetable Tanning in Civilization
The peoples of Egypt and Mesopotamia are believed to be the first to use plant based tannins to treat their leather hides. In different regions, different kinds of plants and trees were experimented with to see what would produce a good leather.
Since the Nile Valley has never had an abundance of trees, Egyptians preferred to use the mimosa plant for tanning purposes, while Europeans used sumac leaves as well as the bark of oak and pine trees. In India and parts of Asia the bark of the babul tree (also known as the gum Arabic tree) has been used for its high tannin's longer than any other in the country. Eventually these vegetable tanning practices were to become the standard by which leather was made.
Foul smelling places, tanneries eventually gained a well-deserved reputation for being disgusting places. Skins from animals were often soiled with blood and dirt, before having to be cleaned and softened extensively.
Once finished, the hides had to be de-haired. This could be done using lime; an alkaline mineral derived from limestone but was just as often done by soaking them in pits of urine. Urine was more convenient in some cases, where all it took to gather it was to pass a few pots around the settlement and collect from all the inhabitants. A mixture of dung water might be added in to help dissolve collagen in the hides, making them more supple and more receiving of tannins.
Once prepared, the raw hides were immersed in pits of water with ground up tree bark and other kinds of organic matter to allow the tannins to slowly penetrate the skin. This process could be punishingly slow depending on the thickness of the hide and the strength of the tannin solution; anywhere between 3 months and 2 years. Once the tannins had fully penetrated the layers and the hide was finished, it would be taken out to dry and dressed with different oils and waxes depending on what it would be used for.
Vegetable Tanning leather would quickly become the standard method of tanning leather in many civilizations around the world. Different plants and tree barks would be used in different regions, and methods would be refined over the centuries of practice.
Leather became more than just a tool for survival: it became a status symbol for the wealthy, a livelihood for those who made it their trade, and an indispensable defense for those who made war. Vegetable tanned leather of great utility and quality would arise from the mastery of tanning techniques, some of which are still known to this day. The domination of Vegetable Tanning would only be superseded in the industrial age, with the rise of Chrome Tanning.
Today tanning looks completely different to when our ancestors first looked for a defense against the cold, or a pair of sandals for their feet. Leather has undergone an evolution no less significant than the evolution of nations themselves. But it’s a testament to this versatile material that it is still relied upon and used even in our modern age, thousands of years after the first experiments in tanning began.
Resources
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