astringency is a complex of sensations resulting from the shrinking, drawing, or puckering of the tissues of the mouth. Earlier, astringency had been considered as one of the primary taste sensations, like sweetness, sourness, and particularly bitterness, with which it has often been confused. It is now recognized as a tactile response not dependent on the taste receptors, however. The word is derived from the Latin ad stringere, meaning to bind, which presaged the finding that astringent materials could bind to, and precipitate, proteins. The most important astringent materials are tannins, and it is these components of a wine that are responsible for the puckery, tactile sensation that is most noticeable in young red wines (but can be sensed in some white wines too, particularly those from hard-pressed or skin-fermented grapes). However, an appropriate degree of astringency contributes very positively to the palatability of a red wine, and astringency is central to the texture and mouthfeel of a wine. Some of the terms used by tasters to describe the astringency of a wine—hard, soft, green, resinous, leathery, gripping, aggressive, supple, for example—are the same as those used to describe the tannins of the wine. The astringent sensation may be modified by acidity, sweetness, phenolics and particularly tannins and pigmented tannins, and even serving temperature. The effect of these components on apparent astringency has been an area of active research in contemporary oenology.