What Is Tanning Leather?


Tanning is the process most people have heard about. Invented in 1858 whether they know what it is or not is a different question. This is when the hide actually becomes leather.

There’s a few different types of tanning:


Chrome tanning is the most commonly used method. This is said to be the most effective.

To get technical, chrome tanning uses Chromium(III) sulfate ([Cr(H2O)6]2(SO4)3). In their original state, tanned hides are blue. Often called “wet blue”. Sulfate is a salt that forms when sulfuric acid reacts with another chemical.


Throughout the tanning process, it increases the spaces between the protein chains. Sodium bicarbonate is also used. This has 2 uses: Increases the PH and prompts cross-linking between the chromium and collagen.

The hydrothermal condition of the skin then increases as it’s resistant to shrinkage.

There are more than one way to tan leather hides, or pelts as they are known before they are processed, you can get veg tanned tanned leather, chrome tanned leather, olive tanned leather, samac tanned leather, synthetic tanned skins, chrome free tanned hides, there are so many ways you can tan leather.

The main purpose of this process is to preserve the hides so that are useable and don’t go rotten.

After soaking of the hides the next process is the following

  • Removes the hair and other keratinous matter
  • Removes some of the interfibrillary soluble proteins such as mucins
  • Swell up and split up the fibres to the desired extent
  • Removes the natural grease and fats to some extent
  • Brings the collagen in the hide to a proper condition for satisfactory tannage


Tanning has to be carried out to the skins or they will putrefy, tanned skins when they get wet or moisture is on them won’t putrefy, where as skins not tanned will be stiff and when wet will rot and putrefy.

Veg tanned leather is possibly the longest process of them all taking around a year to tan a hide, this is done with natural materials like bark, plant matter, leaves from trees and much more, but only certain types of plants can be used for this process.

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