Same as Tannic acid, under Tannic.
An acid present in the stems, pips, and skins of grapes that becomes a very important component of red (and some white) wines. It is also found in the wood barrels used for maturation, where it can alter the balance of a wine.
A substance found in grape skins, seeds, stems and oak barrels (known as wood tannins). Because of this, red wines tend to have higher amounts of tannins than white wines. Tannins also contribute astringency (that pucker feeling when you drink a dry wine) and/or bitter flavors to wine. Tannins also act as a natural preservative, aiding in the aging process.