Just as in commercial winemaking, the longevity of the wine depends on the grape variety and the winemaking style. Long-lived wines are generally those high in either acid (which helps prevent spoilage) or tannin (which helps prevent oxidation). Kit wines are usually drinkable 3 to 6 months after bottling, and may remain at their peak from 1 to 3 years (depending on the grape variety). If you are producing the wine from fresh grapes, some decisions you make will affect the lifetime of the wine. Red wines get their color and tannin from the grape skins, on which the wine ferments for the first few days to a few weeks. The longer the wine is left "on the skins," the more tannic it will become. More tannic wines are astringent and somewhat difficult to drink when young. But they are longer-lived, and produce more complex wines after aging.