Optimum conditions for storing wine include stable temperatures around 55°, humidity of approximately 80%, and darkness. Cool temperatures slow the aging process, increasing complexity and varietal character of the wine over time. Likewise, high temperatures speed the aging process, preventing a wine from developing complexity over time.
It is preferable to store wine at a constant temperature which may a be a bit warmer or cooler than the ideal 55-65 degrees F. Temperature fluctuations cause wine to expand and contract, which causes the cork to push out and pull in and eventually may loosen and expose the wine to oxygen.
Humidity is also important when storing wine. Humidity levels over 80% may encourage mold, while extremely dry conditions may cause high levels of evaporation and exposure to oxygen, spoiling the wine. Wine stored in darkness is more likely to retain its clarity. Light reacts to proteins in the wine to form a haze as well as other unpleasant effects, such as off aromas and flavors.
At home, basements are usually ideal for storing wine because of their cool, constant temperature and darkness. If no basement is available, consider storing wine in a little-used closet in an air-conditioned part of your home. Storing your wine in an un-insulated cold room or fruit cellar will damage your wine during the winter months and may cause the wine to go off. Make sure that your wine is stored on its side so that the wine is in contact with the cork, this keeps the cork moist and maintains the air tight seal.