From the Jul 31, 2005, issue
Think of a grape as a teabag. Both contain flavor compounds that must first be removed from solids in order to impart character to a beverage. With tea, the leaves impart color, flavor and tannins to water. With red wine, grapeskins impart these same qualities to the juice. Compounds in the skin of the grape account for a wine's color, as well as much of its flavor and tannins.