#4 in a series by Peter di Lorenzi
Tannins are the cellulose-derived components of wine contributed by grape skins, seeds, and stems, and by oak aging. The more tannins present in a wine, the more astringent — not to be confused with sour — the wine will be, until natural bottle aging softens their presence in its sensory profile.
In big, concentrated red wines, tannins perform the critical task of neutralizing free radicals already in the bottle and others produced as by-products of the natural aging processes the living wine within undergoes. Without the presence of strong, unpleasant tannins in their youth, such age-worthy reds would oxidize long before they reached their desired plateau of maturity.