The process of leather tanning has evolved over time, but the basic principle has remained the same. Every hide must first be cleaned and purified from all the elements that have soiled it, and then treated with fat to give it back its ‘body’. Tannins are added into the mix that will, so say some, breath new life into the leather. Tannins can either be natural tannins, or chrome minerals. All of our leathers are then finished with a purely aniline dye, the most natural way of adding color to leather. The grain and character of the leather are preserved through the transparent soluble dye that is used, penetrating into the leather instead of being layered on like paint.
Tanning starts today in the ‘Beam House’, since in the past the hide was spread over a wooden beam to carry out these operations. Here, the animal hides are degreased, removed from their hair, and are thus turned into ‘pelts’. Through a process called liming, the epidermal layer of the skin is removed. As a last step, the hides are bated to prepare them for absorbing the tannins.
In the tannery, the hides are tanned in pits or barrels with proprietary ‘solutions’. Here the leather is transformed from an organic hide, to an entirely inorganic material. What comes out is dependant on the tanning agent used, and is called either a ‘wet blue’, for when chromium agents are used, or a ‘wet white’.
Every region in Europe used to be specialized in a different kind of tanning, dependent on where the tannins were sourced from. Tan, derived from the Gallic word for Oak bark Tanno, is usually made from ground up tree bark. France and Italy were well known for chestnut, Germany and the United Kingdom for Oak bark, and Africa for Acacia.
The final place where the leather is treated is called the Currier. Here, two steps are carried out, that of retanning the leather, and finishing. The retanning phase is crucial, since it reestablishes the fat in the leather, and gives the hides their final color.
Before the actual finishing phase, the tanned leather is stretched to dry on a rack, rendering it supple and strong. When completely dry, the leather is finished and ready to be used for footwear and accessories.