VEGETABLE TANNED LEATHER – WHAT IT IS AND WHY WE USE IT?
Vegetable tanned leather – What is that?
Leather is one of the oldest natural materials that already our ancestors appreciated. They made clothing and blankets all from the hides of their hunted animals. Since leather is a perishable material, people started early on to develop appropriate methods to stabilise the raw animal hides, and make them more durable. This process is called tanning.
Vegetable tanning is to process the hides in a pure and natural way without using harmful chemicals. The process is used in order to stabilise the skins and be able to process the resulting leather. It is a traditional, artisanal process that takes advantage of the tannic acids naturally found in some plants, by using the barks, branches, leaves or even some fruits in some specific techniques. The actual tanning process takes between one and three months. This process could be accelerated with the addition of synthetic tanning agents, but this is ineligible for purely vegetable leather products.
Tanning starts with a penetration process, leaving the combination of hides and natural tanning acids rest until the tan is well into the leather. The first tan to reach the leather must be weak in concentration and mellow to prevent tanning the surface early on. With pits a counter current system is normal where the hides move through a series of pits in one direction while the liquors move the other way. The hides go through three sets of pits. In the layers each hide is sprinkled with solid tan material. Fermentation and deposition in the hide creates solid leather in only 3 months. The strong liquors from the final pits are gradually moved down the system while the hides move up from weak to strong. At the end the leather is piled for a few days to completely fix the tan.
Vegetable tanned leather – Why?
A distinction is usually made between chemical and natural tanning methods. The most popular and controversial tanning, due to its widespread use in the fashion industry, is chrome-tanning. It is utilized in 85% of global leather production, which means that in most instances leather is no longer a natural product. The use of chromium salts is harmful to the human health and the environment. Despite these significant disadvantages, it is still the most used method in the fashion industry, mainly because this method is faster, cheaper and less material is needed. Moreover, the further processing is much easier and requires less expertise.
Nevertheless, Melvin & Hamilton has deliberately decided against chrome-tanning and upon the more costly method of vegetable tanning, focusing on the company’s sustainability.
One reason is that a typical Melvin & Hamilton shoe can not arise from another type of leather. No other material can thus be processed and edited meaning that our final product is unique. This is caused by the different nuances and shades used during the multistage dyeing of the leather. Melvin & Hamilton’s typical colour effects could not be achieved with any other raw material. After a chemical tanning the leather is simply dead and thus not breathable, nor it allows an intensive processing and coloration, as is usual in our collections. Furthermore, due to the more gentle processes the average length of life of vegetable tanned leather is considerably higher than that of chrome-tanned leather.
In summary, the principles of sustainability, the versatile and unique processing capabilities and the quality aspects are crucial for our decision to use vegetable tanned leather. As a result, the production and the purchase of goods made from this material are our long-term investment.