Tannins

Tannins are part of a grouping technically called PHENOLIC COMPOUNDS. They are important in the production of a good red wine because they provide flavor, structure, and texture and, because of their antioxidant traits, contribute to a long and graceful aging. Tannins often give young wines a noticeable astringency, a quality that diminishes as the wine ages, mellows, and develops character. Wines with noticeable tannins are referred to as tannic. Tannins are detectable by a dry, sometimes puckery, sensation in the mouth and back of throat.

Quite simply, tannins give sansations of a prickly tongue much like cactus. Ever hear of a red wine referred to as "tight"? TANNINS