Once skins and hides are removed, they are processed for cleaning and the removal of any tissue and hair. This ensures the skin is as clean as possible and ready to be tanned. Leather quality is determined by a number of factors, but the most important is the way the hide is tanned.
Tanning leather involves multiple steps. Depending on the type of process being used, the nature of the hide and the desired result, some steps may be repeated. Consider these various forms of tanning leather:
Brain tanning is one form of tanning leather that does not involve a commercial process. This is done with nothing but the animal itself. The basic process of brain tanning leather is to use materials from the brain, hence the name. The brain lipids are then used to treat the skin, producing a magnificent piece of soft leather.
The process of brain tanning leather actually dates back to the Stone Age when cavemen and hunters would soak the hides in brains, pulling them until they became soft. For these primitive people, this was a part of daily life in making bedding and clothing to stay warm.
Although German and English tanners were brain tanning leather as recently as the late 19th and 20th Centuries, the only thing that remains from the Stone Age Europe are bone and stone tanning tools. The earliest record of European tanning is:
"The ox hide, which is soaked in fat, is pulled to and fro by men standing in a circle, thus stretching the skin and causing the fat to penetrate into the pores."
Additionally, the following tribes and regions have been identified by researchers as having been involved with brain tanning leather:
- Zulu tribe of Southern Africa
- Chukchee tribe of Eastern Russia
- Nomadic people of Asia
- Northern Asia
- South America
- North America
This leaves the softer under layer of the skin. Then the hides are cured in salt and allowed to dry, creating a hard, yellowed “rawhide”, which is nothing like the finished product.
The rawhide is put into successively stronger solutions of brain material, soaked, and then worked with brushes and scrapers to stretch and dry the hide. This process is repeated several times and interestingly, some tanners will smoke the hide as the last step, which produces a handsome hide and rich color as well as a smoky scent.
Chrome tanning, also called “mineral” tanning, is a quicker process compared to vegetable tanning. Chrome tanning leather takes about a day and begins with pickling the skin in an acid-salt mixture. After the skin is pickled, it is put into a solution containing chromium-sulfate. Chrome tanning leather is used to produce a wide variety of garments, especially if the design requires a softer leather.
Vegetable tanning leather produces stiffer result that is still flexible but better suited for sturdier products such as belts and luggage. Hides are placed on frames and hung in vats of tannin, which is where ‘tanning’ got its name.
Tannin is a natural product found in certain parts of trees such as chestnut, oak, and hemlock, using the bark, wood, leaves, and fruit. This process involves the skins being moved through a series of vats. The first vat will have a weaker solution of tannin than the final vat.