Any of a broad group of plant-derived phenolic compounds characterized by their ability to precipitate proteins. Some are more toxic than others, depending on their source. Those derived from nutgalls are believed to be carcinogens, while those found in tea and coffee may be virtually nontoxic. (Hawley's Condensed Chemical Dictionary, 12th ed)

widely distributed polyphenols in plants, particularly abundant in certain unripe fruits, coffee and tea.

A natural component of the wine coming from the skins, seeds and stems of grapes. Most prominent in red wines where it creates a dry and puckering sensation which can dry your mouth. With aging, they form sediments.

n. (L. tannum, oak bark) complex aromatic compounds some of which are glucosides, possibly giving protection or concerned with pigment formation.

A group of chemical compounds that occur naturally in some fruits, such as grapes, and in tree bark and wood -- part of a larger group of substances called phenolics. They are more prevalent in red grapes than in white and are extracted mostly from the skins, seeds and stems during maceration, and also from oak barrels used for ageing wine. Tannins play an important role in helping wines age, but can impart a bitter, astringent taste to young wines.

Complex astringent substances containing phenolic compounds found in plants and usually making the plant material less readily digested. Especially common in bark, unripe fruits and galls on woody plants.

present in tea and coffee and many herbs. Coagulate protein and inhibit the laying down of fatty deposits. Astringent.

Coming from grape seeds, skins, and also from oak, tannins are (along with acid) what give red wines backbone. If you steep tea for too long and your tongue goes all dry and fuzzy when you sip it, that is the work of tannins. Or try licking a banana peel. Or taste a wine from the Madiran region of France made from the tannat grape (whence the word 'tannin' is derived; or maybe it was tana leaves, from the old 'Mummy' movies, we can't remember...). Tannins, given time, generally calm down and 'resolve', precipitating into sediment, which is one of the points of aging wines. Another is the flush of geek pride that comes from being able to say 'Look at all my damn OLD wines! In MY day, if you paid more than forty cents for a bottle of Latour, you was a damn fool...' and so on.

an acidic substance found in the barks of some plants and trees as well as nuts (acorns). Tannins act as astringents, shrinking tissues and contracting structural proteins in the skin and mucus membranes.

A natural substance found in grapes (and black tea, among other things), tannins produce a dry, puckering sensation in the mouth. Most tannins mellow as wine ages (some tannins are not water soluable and they never go away). Some tannin can be a good thing, but too much is undesirable.

substance found in grape skins and seeds that gives a tart flavor and astringency. Red wines are made with the grape skins so their tannins are stronger.

Flavor component derived from grape skins that imparts a bitterness and astringency to the wine; also suggests the longevity of the wine - the more tannins, the longer lasting the wine

Organic compounds found in seeds, stems, and skins of grapes; and to a lesser extent in oak barrels used to age some wines. During wine production, prolonged contact with grape skin, seeds, and stems results in higher levels of tannins. White and rosé wines are produced by minimizing this contact, and so their tannin levels are lower that that of red wines. Tannins produce a bitter taste and the tactile drying sensation of astringency, which may be encountered with young red wines that were designed for prolonged bottle aging, or with white wines produced with excessive skin contact. During aging, tannins are naturally removed from wine, as they polymerize and precipitate out as sediment.

The name for a wide range of complex vegetable acids that are soluble in water. Tannins are natural preservatives that are characterized by a bitter, lip-puckering taste which is described as " astringent". Wines with abundant tannins tend to age well, yet too many tannins also mask the fruity taste of many wines. Aging wine tends to convert the tannins to sediment, and thus removes the astringent taste of "young wines". Tannins are concentrated in the skins and seeds of grapes and are also quite abundant in oak trees and acorns. Thus, wine can pick up additional tannins if it is aged in oak barrels.

naturally-occurring chemical compounds which are particularly concentrated in the skins, seeds and stems of the grape. They are responsible for the bitter, dry taste in wines.

See Polyphenols.

Cheek-drying, astringent phenolic compounds similar to stewed tea in effect on the palate which are found mainly in red wine and are derived from grape seeds, skins, and stems. They can help preserve red wines while they mature in the bottle. Tannin management is one of the red winemaker's most important job.

The group of astringent and bitter compounds found in the seeds and skins of grapes which slow oxidation and promote aging.

A compound which, when bound to protein, can form a haze in beer. Tannins origininate in the malt.

Organic compounds contained in certain cereal grains and other plants.

preservative compounds found in dark grape skins that are an important part of sediment and help the wine ageing process.

A naturally occurring substance found in grape skins, seeds and stems and is also derived from oaking processes causing astringency in excess. Tannins are essential for good balance.

Substances that are produced from the skin, seeds and stems of grapes during winemaking. They add longevity, structure and complexity to wine and are detectable by a dry sensation in the mouth and back of the throat. Wines most likely to be described as tannic are red wines.

Naturally occurring preservative compounds with a slightly puckery, astringent taste in the mouth, similar to the effect of strong black tea or fresh walnuts. Tannins are most evident in young and full-bodied red wines.

Most are derived from grape skins, seeds and stems. Another source of tannins may be from aging in oak barrels. A wine with heavy tannins will usually age longer because the tannins will tend to soften over time, due to a slow oxidation process in the bottle. Tannins usually evoke characteristics of astringency or bitterness, depending on the perception of tannins present.

Organic compounds in grape stems, seeds and skins that add richness and character to wine and act as a preservative for proper aging of red wines.

compounds found in herbs which have strong astringent properties.

Complex polyphenol polymers with a characteristic astringent flavor, extracted from hops and the husks of barley. Tannins react with proteins and contribute to haze formation.

Any of a large group of plant-derived compounds. Tannins tend to be bitter tasting and may function in pigment formation and plant protection.

A substance resulting from the decomposition of lignin in vegetable matter.

The substance in wine that imparts an astringency. Tannins come from skins, seeds and stems of the grapes; adding longevity, structure and complexity to wine. Tannins occur naturally in grapes and sometimes in the wood in which the wine is stored.

Any of a group of water soluble, natural organic phenolic compounds that are produced by metabolism in trees and plants, and are part of the degradation - resistant fulvic acid materials formed during the decomposition of vegetation. Tannins occur in water in almost any location where large quantities of vegetation have decayed. Tannins can impart a faintly yellowish to brown color to water. Tannin molecules tend to form anions in water above pH 6 and can then be treated with anion exchange resins. Below pH 5, tannins are better treated with activated carbon.