A
wine cellar is, in the most general sense, a place where you store
bottles of
wine for the
long term. Wine changes over time, and whether it's for the better or the worse depends very much on how it's stored.
The most important part of storing wine is that you must absolutely keep the temperature constant. The lower the temperature, the slower the wine will age. Recommended temperatures are between 45 and 60 degrees Fahrenheit. Do not allow the temperature to fluctuate very much. This is more important when using an active coolers (discussed in a moment).
Keep the wine out of the light. Light, in both the optic and ultraviolet
range, can damage the wine.
A humidity between 50 and 80 percent is generally acceptable. Too dry of an environment may cause the cork to begin to dry out. Too much humidity may screw up your labels and that's also no good if you like to hang onto those.
Always store the wine lying on its side. This is so the cork will remain wet and continue to make an effective seal with the bottle.
If you live in a place with a basement area with has a constant, cool temperature and humidity, this may afford the best place to store wine. If this area is large enough, you may have room to rack hundreds of bottles. If this is great, more power to you, and I expect to see you getting loaded as often as possible. If this is not the case, or if you're an apartment dweller, you can buy a wine cooler, which is a refrigerator designed specifically to store wine. This is what I have, as my house is built on a slab. Many of these coolers resemble small mini-refrigerators, but use thermoelectric cooling devices so as to cause as little vibration in the wine as possible. These do a fairly good job at regulating the temperature, however it may take a while for the contents to cool off, and opening and closing one too much is not good for the wine. Fill a cooler up with wine, and leave it.
Another important part of cellaring wine is patience, as you might have to wait a little while for the wine you bought to mellow out a bit. Just cellar it, and forget about it for a while. It will still be there when it's time to drink.