Occasionally we get asked about how leather is tanned, so I (Rod) thought I might give a brief overview, which is all most people want to know. This is what the leather looks like when we buy it:
The word tanning originates from tannin, a substance from plants, particularly oak trees. The old traditional method of tanning involves steeping animal hides in vats of tannin-based liquids for months or even years. How this idea was developed cannot be known as it is so old, but for sure it is a fantastic way of preventing animal hide from decaying. The resulting leather has the classic strong leather smell. This leather is often decorated with carved or stamped patterns.
Photo courtesy of Joan Grifols
In Victorian times, when many new chemicals were being developed, a technique for tanning leather in much less time was developed. This uses chromium sulphate salts . The animal hides a are slowly tumbled in huge drums with the chromium salts for just a few days. This leather is more water resistant than vegetable tanned leather, and most bags and shoes are made from it.
These two methods cover the vast majority of tanning. In places such as rural India, much more rudimentary techniques for preventing hides from decaying are used. The most common one is to dry the hide in the sun, then rub vegetable oil into it. This gives the leather a distinctive strong and unpleasant smell, often associated with camels and poor quality bags. We don't use this leather! Rawhide is similarly simply dried animal hide, scraped very thinly.
Various other chemicals have been used for tanning. Cricket ball leather is tanned using a chemical called alum. Alum is interesting in that it was one of the first chemical products ever produced industrially. It was used mainly as a fixative in cloth dying.
Most of the leather used by Pinegrove is cow hide. Some pigskin is used for fine work, and occasionally a little goatskin. This leather is a by-product of farming and is therefore completely sustainable. Leather can be made from the skins of many more animals of course, including fish such as sharks, but we do not use these.
Fishskin items. Photo courtesy of Liegt Vor