Chemical substances from the large group of phenols (Polyhydroxyphenole), which in the barks of many trees, perennials and shrubs as well as in the shells of fruits as for example also in the grapes especially of red wines occur. They serve the plants ultimately as a defense against herbivores or predators and also to protect against microorganisms, Tannins can be a variety of virus inactivate and therefore antitoxic. They also have a very strong tanning effect, so they have been used for millennia for the production of leather. For this reason, they are often colloquially as well tannins but this term is rather negative or pejorative towards tannins.
All tannins are odorless, easily oxidizable and in water and ethanol (Alcohol) soluble. They react with proteins (Proteins). That's why protein opacities in red wines rather rare, since the insoluble tannin protein compounds precipitated and already with the lees be removed. Tannins are a significant part of everything red wines and to a much smaller extent also of White wines, They are for the characteristic astringent (mouth-contracting) effect responsible, by the way, not to the taste, but to the trigeminal Sensory impressions count. Of the bitter Taste, on the other hand, is mainly derived from tannin catechin,
The tannin content in the Wine is mainly from the winemaking ( fermentation and expansion ) as well as from the vine dependent. Among the tannin-rich varieties include, among others Blaufränkisch. Cabernet Sauvignon. Cot (Malbec) Mandilaria. Monastrell (Mourvèdre) Nebbiolo. Petit Verdot. Sangiovese. Syrah and Tannat, Tanninarme varieties or which are with "soft tannins" Carmenère. Cinsault. Gamay. Merlot. Pinot Noir. St. Laurent. schiava (Vernatsch, Trollinger) and Zweigelt, The longer with red wines the duration of the maceration is or the stronger the mash is pressed, the more tannins and anthocyanins (Dyestuffs) get through extraction in the wine.
For white wines, the tannin content is 0.3 g / l, but for red wines it is up to 2.5 g / l (see a list of all wine ingredients below) total extract ). For an objective measurability was the Tanninindex developed. The low proportion in white wines is mainly due to the nature of the winemaking because here at the fermentation As a rule, no combs and grape seeds are involved. Only one Maceration a higher proportion of tannin is also achieved in white wines. Over time, the tannin content in wine softens in a natural way, because of the polymerization Larger molecules are formed as depot to be precipitated and to bottle bottom decline.
The origin of tannins is divided into two groups. The "grape tannins" come from the cores, ridges (combs, stalks) and the shells of grapes; only a very small part comes from the pulp. They are also called flavonoid Tannins, condensed tannins or proanthocyanidins. These in turn consist of Prodelphinidinen (only in bowls and stems) and Procyanidinen (also in grape seeds). These make up the main ingredient in wine. The second group of "woody tannins" with much lower content comes from the wood at one barrel aging respectively. Barrique, These are also called hydrolyzable tannins or ellagannins. By oxidation and sour hydrolysis they decompose ellagic acid and gallic acid, These tannins promote the polymerization of anthocyanins to intensely colored color pigments. They contribute positively to color stabilization and to the ability to age in red wine.
Since the mid-1980s, several techniques have been used in red wine making to improve the taste in the direction of "mild" on the one hand and the positive effect of tannins on the other aging respectively. bottle aging on texture and durability to improve. That's especially true Barrique the proportion of new barrels, the type of oak and the extent of toasting, Regulating the tannin content by beautiful, as well as a targeted, metered oxygen supply means micro-oxygenation, New is the use of oenological tannins (especially Holzbürtige), which are used individually in winemaking: in the maceration, after this BSA, before the barrel aging or before bottling, The not uncontroversial use has any taste-altering effect. There are two negative terms for the tanning taste green tannins and tannin to lose, See also below wine address and wine review,
Oenological Tannin: By Simon A. Eugster - Own Work, CC BY 3.0 , Link
Barrique barrel: By Gerard Prins - Own work, CC BY-SA 3.0 , Link
Grape varieties: Ursula Bruehl, Doris Schneider, Julius Kühn Institute (JKI)