What is tannin?
This common but precious substance is omnipresent in the vegetable kingdom; every plant on earth, of any species, contains tannin. Its purpose is to protect the plant from external aggressions, from animals that feed on it as well as from bacteria, viruses and fungi.
Unlike other living species, as we well know, plants cannot in fact run away from danger, shelter from atmospheric agents or move from an unhealthy environment.
It is therefore thanks to natural evolution that plants have developed tannins as a form of defence.
In fact, plants that are very rich in tannins have an unpleasant taste, which discourages animals from eating them. Not only that, tannins are a strong ally of the plant and exert a real antiviral, antibacterial and fungicidal action.
Tannins are present in every plant, leaf or fruit in variable quantities and have very beneficial properties for animals and humans. For example, the tannins contained in tea leaves, pomegranate and grapes are a powerful antioxidant and are very useful for keeping the guts flora in balance.
In particular to ruminants, tannins are administered as a real supplement since they facilitate digestive processes, promote natural growth and improve the quality of milk and meat.
However, the fields of application of tannins are also many others and are not limited to animal feed. Thanks to its antibacterial properties, tannins are used for tanning leather, ensuring the durability and strength of shoes, bags, accessories, clothing and leather objects.
Furthermore, tannins are an important and natural component of grapes and wine, but thanks to their “multi-task” role they can also be added during the winemaking phase to improve both the production process and the final product. We will explore this theme further on, in the paragraph “Wine and tannins”.
Tannin in history: between leather tanning and nutrition
The use of tannin has very ancient origins and dates back to the time when man was a hunter-gatherer, when by feeding on berries, roots, fruits and leaves, he came into contact with this precious substance with antibacterial and antioxidant properties.
The use of tannins for tanning leather dates back to the times of the Sumerians, who were the first to use this technique and to document it. Later on, it was the Babylonians who perfected it, followed by the Egyptians and the Persians.
In Italy, especially in Tuscany, it was the Etruscans who mastered the technique of tanning and dyeing leather with vegetable extracts of tannin, which has been handed down to the present day.
The Romans then, not only perfected the technique further, but founded the first guilds of arts and crafts dedicated to this and other sectors.
The treated skins were used to make saddles and reins for horses, for military clothing and later to bind books and for many other objects that have accompanied the history of humanity.
Tannin and wine
Tannins in wine are among the main agents determining the colour, taste and the general character of the wine.
When we taste a good full-bodied red wine, one of the first organoleptic characteristics we notice is the astringent effect of the wine on the palate. This effect is given precisely by the tannins which contribute to giving life to a “tannic” red wine.
Tannins are naturally contained in grapes, in particular in the grape seeds (i.e. the seeds contained in the berries) and in the skins of black grapes, and are left to ferment in the must during maceration and fermentation, releasing the characteristic tannic notes.
Even the wood of the barrels releases tannins into the wine through a slow aging process, and it is precisely the combination of the different types of tannins that determines the final character of a red wine.
But that’s not all, the tannins derived from wood, or from other plants such as tea leaves, can be added to the wine during the elaboration and refinement phase, naturally making organoleptic improvements.
Moreover, the water used in the process is purified and reintroduced into the production cycle.
Chestnut Tannin
The chestnut is one of the richest plants in tannin with a content of 10% by weight. The variety that is used is Castanea sativa, or domestic chestnut, very common in Italy and France, which is extracted from adult plants, about 50-75 years old (but this plant is particularly long-lived and can live up to a thousand years!).
Chestnut tannin is used in the early stages of red wine vinification, thanks to its excellent antioxidant and protective qualities of grape polyphenols, providing soft and fragrant notes.
Not only that, the chestnut tannin keeps bacterial development under control, protects the bouquet and fixes and stabilizes the natural color of the wine.
Quebracho Tannin
Quebracho, or Schinopsis balansae, is a typical plant of South America, very common in Argentina, Brazil, Bolivia and Paraguay. It is considered one of the most resistant trees in the world, its height can reach up to 30 m, and it is very rich in tannin.
The total percentage by weight can reach 25%, this represents an exceptional defense against the bacteria that proliferate in these hot and humid regions.
Quebracho tannin is highly appreciated in the oenological field thanks to its stabilizing and antioxidant qualities. Among its main characteristics there is the ability to bind the anthocyanins of the wine, stabilizing them, thus preventing the precipitation of the color that can occur during the clarification phase.
Gall Tannin
The gall, on the other hand, is not a plant, but a vegetable excrescence that forms on the branches and leaves of trees.
Also known as gall nut, this part of the plant is actually a cell cluster that is developed as a self-defense system against bacteria, fungi or insects, which is why it is very rich in tannin.
The use of the gall for winemaking has ancient origins and has various properties, including that of being a powerful antioxidant.
Unlike chestnut and quebracho tannins, gall tannins can be used for both white and red wines.
Green Tea Tannin
The tannins of green tea are instead a novelty in the wine world, they are extracted from selected varieties of high quality oriental teas (deprived of chlorophyll, which is the coloring element of the plant) and represent a valid alternative to chestnut, quebracho and grape seeds tannins.
Among the main advantages of green tea tannins we should mention: the high antioxidant power, the protective action and the maintenance of the olfactory notes of the wine.
They can also be used for both red and white wines and allow you to obtain fresh and elegant wines with soft and rounded notes as a final result.
Tannin and ecology
The fact that the tannin also comes from trees that are cut down can certainly raise questions about the eco-sustainability of this product.
But the answer that comes to us from insiders is instead reassuring, because the chestnut and quebracho plantations, destined for the extraction of tannin, are managed responsibly and are regulated according to national regulations.
The forests populated by these plants are not intensive plantations, but natural forests created by nature where biodiversity reigns.
Protecting these forests is in the best interests of producers, because indiscriminate use of these precious resources would compromise their long-term productivity.
Furthermore, the tannin extracted from plants is a 100% vegetable product which is harmless to the environment.
How is tannin extracted?
Even the tannin extraction process has a very low environmental impact and has remained unchanged over time, since the wood is immersed in hot water without the addition of solvents or chemicals.
Oltretutto, l’acqua utilizzata nel processo viene purificata e reimmessa nel ciclo produttivo. While the exhausted wood is used for the production of pellets for stoves or sent to biomass power plants, to further reduce waste.
But it is not only the environment that is respected; even the communities that live near the plantations benefit from the job opportunities created by this sector in rural places that would otherwise risk abandonment.
In the case of the tannin industry we can therefore speak of a real green and circular economy, where man and nature cooperate in harmony, proving that sustainable development is possible.
Finally, we would like to remind you that Geber distributes specific tannins for refining available individually or with customized blends on request.
If you want to find out more, visit the page dedicated to our oenological products and contact us using the form with your specific requests, we will get back to you as soon as possible.
