Chemical substances from the group of phenols (polyhydroxyphenols), which occur in the barks of many trees, shrubs and bushes as well as in the skins of fruits and also in grapes, especially of red wine varieties. They ultimately serve as a defence for plants against herbivores or predators and also as protection against microorganisms. Tannins can inactivate a large number of viruses and therefore have an antitoxic effect. They also have a very strong tanning effect, which is why they have been used for thousands of years in the production of leather. They belong to the large group of tanning agents, which is also used as a synonym
, although this term tends to be negative or pejorative towards tannins.
Tannins in grapes
The tannin content in wine depends mainly on the vinification (fermentation and ageing) as well as on the grape varieties. Varieties rich in tannins include Aglianico, Alicante Henri Bouschet, Blaufränkisch, Cabernet Sauvignon, Cot (Malbec), Mandilaria, Monastrell (Mourvèdre), Nebbiolo, Petit Verdot, Sangiovese, Syrah and Tannat. Low-tannin varieties or those with "soft tannins" are Carmenère, Cinsaut, Gamay, Garnacha Tinta, Merlot, Pinot Noir, St. Laurent, Schiava (Vernatsch, Trollinger) and Zweigelt. The longer the duration of maceration in red wines or the more strongly the mash is pressed, the more tannins and anthocyanins (colouring agents) are extracted
into the wine.
The main part in the wine comes from the seeds, crests (caps, stems) and the skins of grapes; only a very small part also comes from the pulp. That is why they are also called "grape-borne...
