The word for tanning comes from medieval Latin tannāre, a derivitive of tannum (meaning oak bark). This refers to use of the bark of oaks (the original source of tannin) in hide preservation. The presence of abundant quantities of oak, the plenitude of waterways and access by the Loire to the port city of Nantes made the Touraine an ideal region for the establishment of tanneries.
Historically, because tanning was such a noxious or “odiferous trade”, it was carried out on the outskirts of towns or villages by the poorest sections of society.
It could take between 24-30 months to transform raw hide to leather. The basic process was as follows: dried and bloodied skins would arrive at a tannery and tanners would soak the skins in water to clean and soften them. Then they would pound and scour the skin to remove any remaining flesh and fat. The tanner then removed hair fibers by either soaking the skin in locally collected urine, painting it with lime, or by letting the skin putrefy for several months before dipping it into a salt water solution. After the hair fibers were loosened, the tanners scraped them off using a broad knife (see image). Once the hair was removed, the tanners would then pound animal or bird dung into the skin or soak the skin in a solution of animal brains to soften the material.
This heavy, dirty work was always redolent of the inescapable odours of decaying animal flesh. The out-flow from skin-washing and cleansing of the tan-pits was highly polluting to the streams and rivers of the region.
Any leather that was leftover from the process would be turned into glue which was prepared by placing the scraps of hides in a vat of water and letting them deteriorate for months. The mixture would then be placed over a fire to boil off the water to produce hide glue.
So, keep your eyes open on your travels for the often narrow, winding streets named Tanneries which lead down to the river in many of the towns in the Touraine.Sources: Wikipedia The Tanneries in Château-Renault