The period of time from when the wine is made to when it's served, aging can last anywhere from a few weeks for jug wines to 15 years or more for ultra-premium wines. Most wines are aged in barrels, vats, stainless-steel tanks, or bottles, preferably in cool, dark, and moderately humid conditions. The purpose of aging is to let the wine develop additional flavors (imparted from oak barrels, for example), softer tannins, and a smoother texture. Extended aging, however, is intended only for a small portion of ultra-premium wines to increase both their value and complexity. Most of today's premium white wines are ready to be consumed before they are two years old, and most commercial and premium reds before they are four or five years of age. Any longer and the wine may lose its flavor and become tired. See also barrel-aged and bottle- aged.