Bating and Pickling
Bating and pickling make the fibres of the hide more receptive to tanning.
Hides are treated with enzymes, similar to those found in the digestive system, to break down proteins. As a result the hides become softer. The duration of the bating process depends largely on the desired softness of the leather being produced. The softer the leather required, the longer the bating process.
Bird droppings and dog faeces have were known to have been used for this procedure prior to the development of industrially-produced chemicals.
This process makes the fibres of the hides more receptive to tanning. Pickling increases the acidity of the hide to a pH of 3, enabling chromium tannins to enter the hide. Salts are added to prevent the fibres from swelling. For preservation purposes, fungicides and bactericides are used.
Skins from smaller animals such as goats and sheep are usually sorted according to quality after the pickeling.
Old tanners tell of how long ago tanners tested the pH of pickled hides by biting on a piece of hide, which over time started dissolving the front teeth. Nevertheless, many tanners initially found it difficult to trust ph test paper or liquid indicators, which then prevailed.
Videos about the leather production
The leather production in a modern tannery.
|Process steps in the leather production|
|storage - soaking - liming - fleshing - splitting - pickling - tanning - neutralising - withering - sorting - shaving - dyeing - fatliquoring - retanning - drying - finish - softening - final check|
|Chrome tanning - Vegetable-tanned leather - Synthetic tanning - Tanning with fats and oils|