Tawing with alum

Tawing with alum - Alum tanned

Tawing is a method of tanning with aluminium salts (alum). It is a naturally-occurring double salt, but which is also artificially produced. Tawing comes under mineral tanning and is one of the oldest tanning processes. After tanning with alum, the dried leather is stiff and firm. To make it softer, the leather is then tumbled and greased.

Alum tanning makes the leather white and very water-sensitive. The tannins are washable, making this leather much more sensitive than with chrome tanning which, with a few exceptions such as for Sheepskin, has replaced alum tanning.

Alum tanning: Sheepskin and leather straps.

Alum tanning: Leather belt with braided parchment.

Alum tanning: Cricket ball from England.

Glacé leather

Glacé tanning is a form of traditional white tanning and is based on natural ingredients. These include alum (aluminium sulphate), salt, egg yolk, wheat flour, fats and water. The tanning itself is a very short process, which takes only a few hours.

Glacé leather has traditionally been used as glove leather (usually goatskin).

Nowadays glacé leather is described, when the tanning method is not clear. Leather with "glacé effect" is also offered. In such cases, the tanning method is then deviated. It's generally not clear what is meant by "glacé effect".

Glacé gloves are very sensitive to water due to the non-permanent, washable tanning. The ring finger of this glove was irreparably damaged by moisture.