At a basic level, wine is chemistry. A good wine is a highly specific mixture of amino acids, phenols, carbohydrates, and alcohol, as well as traces of oxygen left over from the bottling process. Each of these components acts on and influences the others, creating a complex series of chemical reactions that give wine its flavor. These reactions are driven primarily by three environmental factors: light, humidity, and temperature. If these factors are not carefully controlled as the wine ages, the chemical reactions inside will spin out of control and ruin it. How do you control each of these factors to ensure your wine tastes great when you open it? What are the ideal conditions for wine storage?
Sunlight, particularly ultraviolet sunlight, breaks down the tannins in wine. Tannins bind to oxygen and prevent oxidation from occurring. If left unchecked, oxidation can cause premature browning or transform alcohol into acetaldehyde, which spoils the wine. This is why wine should always be stored in a dark area, out of direct sunlight. Ambient light from bulbs or fluorescents are not strong enough to affect bottled wine.
Humidity does not affect your wine. It affects the cork. Corks are made from bark and will either rot or dry out if your storage conditions are too dry or too humid. If the conditions are too dry, the top of the cork will gradually lose its moisture and shrink or crack, allowing additional oxygen to seep in and upset the chemical balance of the wine. If conditions are too humid, mold can grow, damaging the cork and the label. Both processes take a long time, months or possibly years, but can be prevented by keeping your wine in an environment with 50-70% humidity.
Temperature is the most important factor when storing wine. The chemical reactions that give a wine its unique flavor are accelerated when the wine is placed in a warm environment, but this acceleration isn’t uniform. Some chemical need high amounts of energy in order to react, some need low amounts, which is why you can’t speed up the aging process by increasing the temperature of your storage space. The opposite is also true. Storing a bottle of wine in a low temperature environment slows the chemical inside of it, but not at the same rate. In order for wine to age properly, all of the chemical reactions need to happen at the same rate.
The ideal temperature for wine storage is 55°F. This allows the chemical processes in the wine to proceed as intended and allows your wine to age properly. The temperature should be stable as possible. Temperature fluctuations, even minor ones, cause wine to expand and contract as it heats and cools. When wine expands, it places pressure on the work, pushing it forward in the bottle, which allows wine to evaporate. When it contracts, it pulls the cork back into the bottle, which pulls in additional oxygen into the bottle and upsets the bottle’s chemical environment. This is the reason why modern wine coolers have such rigid temperature controls. Controlling the temperature is the best way to age and preserve your wine.