Vegetable tanning general
Vegetable-tanned leather, also known as vegetable-tanned leather, is tanned with a purely vegetable tanning agent. This tanning method was predominant for many centuries. Today, however, only about 10-12% of leather is tanned with vegetable tanning agents.
In vegetable tanning, the leather is tanned using an active ingredient found in oak and spruce bark, olive leaves, quebracho wood, tara pods, and mimosa bark, among other things. These tannins are produced and stored by plants and serve as a defense against predators. There are up to 300 plant species worldwide that contain this valuable tanning agent. All Gusti-Leder Nature products are tanned with the bark of the babul tree.
Types of vegetable tanning
There are two types of vegetable tanning. In pit tanning, the hides first go through the "dyeing" process and then the "sinking" or "batch" process. The entire process takes approximately 20-30 months, significantly longer than chrome tanning, which only takes a few days. To speed up the tanning process, pit tanning is combined with barrel tanning, which uses a more concentrated broth. However, due to the time savings, the aim is to tan the majority of natural leather using barrel tanning alone.
Properties of vegetable-tanned leather
To tan a single hide, you also need approximately 30 kg of bark or 20 kg of fruit. The finished leather will have different properties depending on the acidity of the tanning solution in which the hides are tanned. Acidic tanning solutions, with a sufficiently long tanning time, produce relatively strong leather. Sweeter solutions, on the other hand, produce a softer leather.
Dyeing of tanned leather
Vegetable-tanned leather, or natural leather, can be identified by its brown (tan) color. In undyed leather, this color can darken due to factors such as light, moisture, and oiling. The drier the leather, the lighter it becomes. Therefore, vegetable-tanned leather should be treated regularly with leather conditioner.
In this video you will learn how natural tanning without chromium salts works:
Additional sources (accessed 22.12.2018):
- lederpedia(dot)de/lederherstellung/tanbung/pflanzeliche_tanbung_tanning_verfahren_und_durchführung
- leder-info(dot)de/index.php/Vegetable_tanned_leather
- lederzentrum(dot)de/wiki/index.php/Vegetabile_Gerbung
- lederpedia(dot)de/lederherstellung/tanbung/pflanzeliche_tanbung_mit_tanbstoffe_und_extrakte
