Regardless of the quality and cut of the leather it is never going to make it into a pair premium Sanders, Trickers or Loake shoes unless it is processed properly. The history of tanning goes back at least 2,500 years to the Sumerians and in all likelyhood considerably earlier.
Traditionally leather tanning was relegated to the outskirts of a town for very good reasons: it was a filthy and foul smelling business due to its reliance on animal faeces. Today the industry is sophisticated and uses two main techniques: vegetable and chrome tanning. However many tanners guard their tanning ingredients very closely and use their own special techniques and additives to give thir finished product the edge over any competition.
Initially both techniques are fairly similar. The hide will first be soaked in salt water and then an alkaline lime treatment will loosen the hairs prior to mechanical removal. A process known as scudding. It is at this stage that the hide may be assessed.
The outer or grain side is inspected for flaws and a buffer may be used to remove any imperfections. However this will also remove some of the topmost layer and may weaken the leather. So the term full grain leather used by Sanders, Trickers and Loake means that the top layer has not been buffed off.
Vegetable tanning takes considerably longer than chrome tanning but the resultant hide will usually be heavier, stronger and more water-resistant leather. It wears well and tends to be better at holding its shape. The process involves soaking the hides in plant tannins over a period of months whilst the concentration of the tannins get progressively stronger. The hides are then washed and dried before being lubricated with oils and fats to improve suppleness, provide water resistance and to give the leather long life. This is a slow process and it can takes months for the oils and fats to thoroughly penetrate the hides. Finally the currying process dresses and finishes the hides with more oils, fats and dyes. A cheaper leather will have these sprayed on whilst quality leather is finished by hand.
Chrome tanning is a much faster process and takes days instead of months. The hides are soaked in chromium salts. This will produce a strong leather but one which is prone to stretching and won’t absorb oils and fats as well as vegetable-tanned hide, and tends to be less rigid. Its water resistance is poorer, but additional treatment can rectify this.
Consequently Sanders, Tricker and Loake will always prefer to use vegetable tanned hides over chrome tanned ones.