CURIOSITY ABOUT TANNING
Leather tanning has an ecological function that is often overlooked. Yet it allows you to recover and ennoble a by-product of the food industry that would otherwise risk becoming waste to be disposed of.
Tanning is one of the most remote human activities: men, in fact, have always used animals that they hunted and bred to obtain clothing or shelter. At the beginning, however, the temperature was a problem: the heat caused the rot of the skins, while the cold stiffened them. We had to find ways to make them unalterable. In all likelihood, they began to use greases that provided greater strength and flexibility. Certainly smoking and tanning with aldehyde, derived from the vapors of the burnt foliage, became widespread techniques, but it was soon evident that the best results were obtained with drying. Over time, the processes became more and more refined, also differentiating according to the geographical areas: alum tanning, for example, took hold in volcanic areas, while tannin vegetable tanning in the vicinity of oak woods.
During the 8th century, under the dominion of the Moors, the Spanish developed the production of leather which became famous throughout Europe, the Cordovan.
The ability to work skins, however, was not an exclusive prerogative of the western world: in "Il Milione" Marco Polo told of how the Mongols used water bottles, blankets, masks and leather caps, often finely decorated.
Later, around the twelfth century, the depilating effect of quicklime introduced such an improvement in tanning that until the last century there were no substantial changes. On the other hand, there are two innovations that made it possible to significantly reduce times and also found application in industrial production such as the use of chromium salts and the replacement of traditional tanks with revolving drums, as well as the discovery of new types of tannins.