Tannin is a naturally occurring component of the skins, seeds and stems of wine grapes. It is present most often in red wines, where the juice soaks in the skins to obtain the red color. During the aging process, the tannins bond with the color pigment in the wine and then settle as a deposit in the bottom of the bottle. Tannins result in an astringent, dry texture while drinking the wine. Generally, the deeper the red color of wine, the higher level of tannins present. As Cabernet Sauvignon grapes have the thickest skins, the wine is most tannic. In the making of White Zinfandel, the wine is made with very limited contact with the skins, resulting in a light blush wine with little tannins. Wines with heavy tannins, such as Cabernet Sauvignon, and Red Bordeaux, often improve and soften with age, allowing time for the tannins to integrate with the wine. Such wines often produce sediment, which settles to the bottom of the bottle. These wines should be decanted to leave behind the sediment when pouring into the glass. Wines with a lower tannin level will feel smooth, soft and silky, while those with a higher level will seem firm and more structured.