Wine is finicky and has specific requirements for how it needs to be stored over a period of time to age properly. The nitty-gritty details of this aging process can be summarized simply: it’s a chemical reaction between the compounds found in wine (amino acids, phenols, tannins, carbohydrates, etc.), the small amount of oxygen already sealed into the bottle, and the oxygen that will seep into it as the wine breathes through its cork. This process is delicate and can be affected by numerous outside elements, so it really is pertinent to construct your storage unit and/or conditions around the five following points...
Wine needs to be stored at a constant temperature between 55-60°F (or 13-15°C). Heat is your wine’s number one enemy. At 70°F or higher your wine will age faster and fall victim to one or both of the following side effects:
Cooked: when wine is too hot for too long it will have flat/stewed aromas and flavors. This is not something that can be remedied by chilling the wine for any period of time. Once a wine is cooked, it is irreversibly damaged.
Cork Failure: when the temperature of a substance rises or cools, it expands or contracts. When the wine expands, the cork seal could fail and partially pop out of the bottle. Once this occurs, there’s a much greater chance of cork failure. The wine could slowly seep out of the bottle, the increased oxygen exposure could damage it, or the wine could become contaminated by chemicals or bacteria.
Wine is mostly water. On principle, water collects and retains heat, and the average chemical reaction is increased by higher temperatures. Heat adds more energy to the wine, increasing how fast these reactions happen, and causing them to accelerate at different rates; this leads to an imbalanced wine.
Wine will freeze between 15-20°F. Just the same as with too much heat, when wine hits these temperatures, it will expand and put pressure on the cork, retracting into the bottle once brought back up to temperature. That being said, wine kept colder than recommended is not nearly as bad as it being kept hotter than recommended.
Consistency is key! Keeping the temperature constant is more important than the actual temperature it is kept at (within an appropriate range). Fluctuations over a short period of time will have no ill effect on your wine. However, if the temperature changes on a day to night basis (and even season to season), there will be tangible effects. Fluctuations allow more oxygen and air into the wine. When it gets hot and expands, air will seep past the cork, and then when it cools again and contracts, more air will be drawn in. This air coming in from the outside replaces the slowly evaporating wine. This will affect the ullage and create a lower fill than expected for the age of the wine.
The relative humidity levels of your wine cellar should range between 60-80%. Cork is a natural product, so it will deteriorate over time. Even if you’ve placed the bottle on its side, the cork could still potentially dry out, meaning it will crack and shrink. When this happens, more air is allowed to enter and exit the bottle.
The good news is, is that you probably won’t have to worry about this being a problem unless you live in the desert or the arctic. If you are concerned your cellar may be too humid or not humid enough, here are some tips:
Below 60%: You can counteract the lack of moisture in the air by placing a pan of water or a humidifier somewhere in the cellar.
Above 80%: There’s no danger to your wine or the cork with too much humidity, exhibited by French cellars covered in mold. You are, however, inviting mold or mildew to damage your store room and you risk damaging the wine’s label. A dehumidifier can fix this problem.
100 year-old French cellar covered in mold (Credit: Amos Chapple)
Keep your cellar dark. Wine shouldn’t be exposed to excessive amounts of light. Light, especially the short wavelengths like UV, breaks down the complex molecules that can be attributed to certain flavors in properly aged wine. Most wines have built in protection with the darker colored glass, but avoid light as much as possible. Like heat, light adds energy to the wine, causing reactions to increase and change more rapidly over time.
If possible, use incandescent bulbs over fluorescent lights, as these emit smaller amounts of UV waves.
Air Quality / Ventilation
As mentioned multiple times before, wine breathes through the cork letting oxygen in over time (and this is a completely natural part of the aging process). The molecules that make up an odor will seep into the wine too. So, it stands to follow that the air quality of the cellar should be clean; otherwise you risk ruining the flavor and bouquet of your wine.
Some odors are benign, and others more harmful, like chemical compounds such as fresh paint and cleaning supplies. Aromatic food products like garlic will seep into your wine as well, so be careful what you store near your cellar.
Extended periods of