Tannin: What is it?
Tannin is a natural substance present throughout the plant kingdom: in wood, bark, rhizomes, roots and fruits. It is part of the polyphenols family, a term that you may have already heard.
Polyphenols are antioxidant substances found in fruits, vegetables and, in general, in different plants, which help to preserve tissues against cellular ageing.
As a result, tannin is 100% natural.
The “family” includes different molecules, so that it would be more correct to ask “what are tannins?” The difference lies in their chemical structure and their different botanical origins.
But all tannins have common characteristics that have allowed them to become silent companions of the whole path of human civilization, from the ancient times until our days.
Tannin is natural at:
What Are the Properties of Tannin?
Have you ever wondered why, after a thunderstorm, the damp wood of the trees does not begin to rot?
Or how can aquatic plants survive, like mangroves with their trunk and roots plunged into the swamp water? Tannins are the reason. Their chemical structure confers them the property to counteract fungi and bacteria’s activity, and it’s so powerful to act even in water.
Unlike most animals, plants cannot move: they have developed tannin as a natural protection from the onslaught of pathogens, such as fungi, bacteria and viruses. Once extracted from the plants, its characteristics remain unchanged. Even after a long time.
This paves the way for various possible applications, some of which will surprise you.
How to Extract the Tannin?
The procedure to extract tannin recalls closely that of an infusion: the vegetable source (e.g. Chestnut and Quebracho wood) is shredded and poured into gigantic autoclaves that act as “teapot”.
In contact with hot water, the wood releases tannin: The water is tinged with a beautiful color that varies from brown to reddish according to the wood used and its scent is very strong.
Tannin is now ready to be used in liquid form but, to make transportation and conservation easier, an evaporation of the water is carried out to obtain a fine colored powder.
The water vapor is recovered and re-processed into the vats for new infusions. The exhausted wood is transformed into useful pellet for heating stoves.
Where is Tannin in Nature?
Tannin is present in wood, stems, barks, leaves, roots and fruits of any plant species.
However some plants, being more rich in tannin, are the most used raw materials for industrial level extraction. We are talking about Chestnut, Quebracho, Tara and Oak Galls.
The Chestnut tree is widespread in southern Europe and in some parts of the Middle East.
Quebracho grows in the North of Argentina and in the South of Paraguay while Tara grows in Peru. Galls grows predominantly in Turkey and China.
If you own a vegetable tanned leather item, like a purse, a wallet, a belt; if you wear leather sole shoes or you have a car with leather seats, it is very likely that it has been treated with Chestnut tannin, Quebracho or Tara or with a combination of two or more extracts.
Is Tannin Extraction a Sustainable Process?
Maybe you are thinking that to extract tannin you need to cut down the trees and you are concerned about the integrity of the woods.
But tannin also protects the plants from the greed of Men, which too often destroys forests to make room for intensive cultivation, as in the case of soybean crops.
The possibility to extract the tannin has however given the woods a different economic relevance.
As a result, the trees become valuable: for every old trunk torn down, there is a new tree that is left to grow naturally or that is planted to ensure the maintenance of the raw material source.
A “win-win” alliance between Man and Nature.
Can Tannin Help Balancing the Bacterial Flora?
Yes, tannin brings the bacterial flora back to its natural equilibrium, and at high concentrations it can be defined as a real natural antibacterial.
A recent university research has reported that tannin contained in vegetable tanned leather can eliminate more than 99% of the bacteria it comes into contact with.
In our daily life, this action can particularly affect the population of bacteria responsible for the bad odor inside the footwear.
Unlike the common disinfectants and deodorants for shoes, the tannins action is not temporary but long-lasting in time. It also takes place in harmony with the natural physiological processes of the foot.
The History of Tannin
Part of Your Own
The school books do not speak of tannin, yet his presence has affected the entire history of Mankind in a relevant way, with really unexpected implications.
For example, tannin played a role in determining the outcome of the Second World War. Could you believe it?