After paying a lot of money for a nice bottle of wine, the last thing you want is to open it and be greeted by the smell of wet cardboard, cooked cabbage, and a total lack of any fruity characteristics. These can be some of the consequences of improperly stored wine.
Temperature plays an important factor in the proper storage of a wine because high temperatures will rapidly increase aging, and depending on how hot the temperatures are, can “cook” your wine. Higher temperatures will result in a ruined wine, so definitely think twice before leaving your wine inside the hot car for the day!
White Wine...
White wine should be stored at a little cooler temperature than red wine. This ideal temperature range should be between 45 F and 55 F. Now I realize this is a somewhat awkward temperature as it is cooler than room temperature, but a little warmer than the refrigerator. Some people have wine refrigerators that they can set to a certain temperature. If this is not the case for you, then I recommend to stash your white wine away in a cool, dark spot in your house - think coat closets, cabinets (away from the oven), basement, etc.
The reason why a dark environment is important for white wine is because any ultraviolet rays that hit the wine will cause it to start degrading prematurely by changing its chemical composition. White wine is typically in clear/light glass which makes it even more susceptible to light exposure. This is not as important of a factor for red wines because (1) they typically are in darker colored glass, which leads to more protection and (2) they contain a phenolic compound called “tannins” which serve to protect against the aging process of a wine.
Red Wine...
Broadly speaking, red wine is a lot less finicky than white wine. Reds should ideally be stored at 55-60 degrees F. Especially during the winter months, red wine can more easily be stored on the countertops (remembering to stay away from the oven or any other heat sources).
Now, when it comes to which way to store your bottles, that depends on what type of closure your bottle has. For bottles with corks, they are best stored on their side (horizontally). This ensures that the cork doesn’t dry out as much and, therefore, is able to keep oxygen out of the bottle easier. Just as light and temperature are able to degrade a bottle of wine very quickly, so can oxygen. As far as screw caps go, they can be stored either vertically or horizontally which makes things a little easier when considering space!