Vegetable Tanned Leather: What is?
Vegetable tanned leather is obtained from the processing of raw animal skins through the use of shredded plant rinds, rich of tannins, to which water is added and then the hides are left to soak. During the vegetable tanning process, the tanning substances are slowly fixed to the leather fibers in order to obtain a rot-proof material. This special processing makes vegetable leather versatile and suitable for customization and hand finishing. Vegetable tanning is the oldest and has prehistoric origins, unlike chrome tanning that is much more recent. Vegetable tanned leather belongs to the category of ecological leathers as it is characterized by the use of only natural substances, as tanning agents, for this reason it is not harmful to humans and the environment.
Tannins are used to tan the leather, they are present in some plants such as mimosa, chestnut and quebracho. They are derived by shredding the bark of these plants in order to obtain a powder which, when mixed with water, allows the tanning, that is to say the stable and irreversibly fixation of the fibers of the dermis of the skins. Tannins are therefore tanning agents that are able to fix themselves stably to the animal skin fibers and prevent their decay and putrefaction.
How Vegetable Tanned leather is made (Step-By-Step)
The vegetable tanned leather production process consists of five main steps:
- Riviera works
- Re-tanning and fattening
The “riviera” works represent the preliminary phase and have the purpose of preparing the still raw leather for the following stages of production. It includes the following steps: soaking, hair removal, liming, deliming, fleshing and pickling.
Once the riviera phase is over, the leather is not yet tanned, but it already has a certain degree of stability that allows it to be preserved for a certain period of time. Later, the pre-tanning phase begins, from which an intermediate product called “wet-white” is obtained. Then there is the tanning stage in which the leather is tanned with water, mostly in large barrels, called drums, which by rotating facilitate the penetration of tanning agents, fatteners and any dyes.
Once tanned, the leather is obviously still damp and with the drying process it begins the fourth phase, that consist of drying the skins in the air or inside ovens; subsequently then the last phase takes place, that of finishing where the leather hides pass through various stages of finishing according to the requirements to be obtained. In reality, once dried, vegetable tanned leather needs very few refining processes, simple mechanical operations are enough to soften and stretch it, and then it can be immediately used for the production of finished products. If it is not even colored, it keeps the original colors of the bark of the plants used: it goes from a light beige color using the various types of mimosa, to a more reddish-brown beige with the use of quebracho, up to a more intense brown with the use of chestnut bark. Often a “cocktail” of the various tannins is made to obtain the desired result.
Advantages and disadvantages of veg tan leather (Benefit)
The advantages of vegetable tanned leather derive above all from the fact that it has characteristics of greater vitality and reactivity than a chrome tanned leather. Vegetable tanned leather is defined as “more alive” and less stable than mineral tanned leather. It needs more care and precautions during production, but it has a natural appearance especially when associated with various greases and oils that make it very reactive and can be polished simply by rubbing it. On the other hand, it is less resistant to water penetration and humidity to the point that mold can form if not treated; it can also change color more easily when in its natural unfinished state if exposed to the sun. Further limitations derive from the low heat resistance, especially with modern shoe manufacturing techniques that include soles in synthetic materials at high temperatures. Vegetable tanned leather, in fact, will never be used for the production of sneakers, because it tends to deteriorate irreparably at temperatures above 70/80°C. Moreover, vegetable tanned leather has a lot of usage limits for modern production of decor objects, such as sofas and upholstery in general. On the other hand, it is perfect for creating designer chairs and luxury desks. Finally, there are also limits to be considered for use in clothing industry: vegetable leather has no particular anti-tear qualities and breaks more easily, especially if at very low thicknesses required by the clothing market for elegant and very fine garments.
How to care for Veg Tan Leather
The care and maintenance of vegetable leather are usually very simple, you can use oils such as straw oil or ox foot oil, mixed with 30% of mineral oils, which penetrate into the vegetable leather give an even more beautiful and rich appearance. Alternatively, you can use our natural made Balzam for leather.
Appearance of veg tan and changes in time
A natural vegetable leather is subject to change color towards reddish or a more intense brown, especially when subjected to light. However, this does not represent a limit, on the contrary, it is often considered an added value and in any case is less evident in drum-dyed or fully finished vegetable leather. On the other hand, if the vegetable leather is oiled, such as the traditional “tallow” (sego) tanning with ox fat (also called vacchetta), it tends to improve over time becoming more and more beautiful.