The addition of wine making tannins and oak help winemakers bring out specific flavor profiles they're in search of. Tannins, literally meaning "zest" or peal of the grape, have multiple benefits. First tannins assist with bringing out the zesty flavors of wines, and help clarify the wine by pushing proteins to the bottom of the fermenter. Tannins also help maintain and enhance the characteristics of wine through the aging process. Wines deficient in tannins generally do not reap the benefits of aging.