Once you have made your wine, and gone to so much trouble getting it into the bottle, NOW is the time to think about how you are going to store it. Get this wrong and you might just as well have not bothered to make the wine in the first place.
There are 3 storage conditions of concern:
- Light
The storage area for wine must be dark because ultraviolet (UV) light will damage wine by causing the degradation of otherwise stable organic compounds found in wine. Since these organic compounds contribute to the aroma, flavour and structure of the wine, the changes caused by UV light result in the deterioration of the essence of wine. (Note: Fluorescent lights emit a significant amount of UV light.)
- Humidity
The only reason humidity is an issue in wine storage is because of the use of the traditional cork seal. The relative humidity of the storage area (i.e., the amount of gaseous water in the air) can exacerbate the rate of evaporation of wine from the bottle if the cork is defective. Since corks are far from perfect in their ability to seal a bottle of wine, ullage (the space between the bottom of the cork and the wine level in the bottle) develops in almost all bottles stored for extended periods due to evaporation. If the cork (seal) is defective, low humidity in the storage area will result in wine moving out of the bottle faster over time and significant ullage will develop in less time under these conditions. Thus, the more important issue is the quality of the cork seal and not the relative humidity in the storage area. Of course, very low humidity can dry out the cork leading to sealing problems.
Relative humidity levels can be anywhere between 50 and 80 percent. Cork is a natural product and will deteriorate with time. And yes, the top end of the cork will still dry out even when the bottle is placed on its side and the bottom end of the cork is in contact with the wine. A dry cork will shrink, crack, loosen and allow more air to come into contact with the wine. The problem is made worse if low humidity is accompanied by temperature fluctuations. High humidity levels will keep the top of the cork from drying out. Humidity below about 50% RH is getting too dry. Levels above 80% will not damage the wine, but can create the risk of mildew forming on the cork and labels.
- Temperature
Wine must be kept in an environment where temperature is constant and stable. An acceptable level of temperature fluctuation is said to be about 2-3ºC (5ºF) around the average once per year. Temperature stability is the “holy grail” of wine storage. It is the most important of the storage requirements, and at the same time one of the hardest ones to achieve. For those using home storage methods, a 5ºF temperature variation can be a daily occurrence. Moreover, if you think your wine cabinet, your cellar, or your current storage provider is doing a good job, try leaving a Max-Min thermometer in the unit for a few months. I think you’ll be surprised. Maintaining constant temperature over time is even more important than the actual average temperature level. Fluctuations in temperature allow more air/oxygen into the wine. As the environment warms up, the wine (and air) in the bottle warms up and expands. The only thing that can give is the cork. Either the cork moves out slightly, or some of the air (or wine when stored on its side) will push past the cork. As the air cools, the contents of the bottle will contract, drawing air/oxygen into the bottle. Over many temperature fluctuations, quite a bit of this outside air can actually replace the wine. This leads to the low fill level or ullage seen in older bottles. Since high levels of oxygen, a highly reactive gas, is the single most damaging thing to wine, bottles that have undergone repeated temperature cycling tend to loose their freshness (at best) or spoil (at worst). For wine to age in a proper manner, temperature fluctuations must be minimized in both magnitude and frequency. Fluctuations of only 1.5ºC (3ºF) can be very damaging to wine if they occur on a daily basis.
The ideal temperature for wine storage is 13ºC to 14ºC (55ºF to 57ºF).
Now some of you may be thinking, “Why not just store wine in my closet? It will simply age faster, and I can enjoy it sooner?” Bottles stored to peak quality at higher than proper cellar temperatures will always be inferior to a bottle stored to peak at the correct temperature. And here’s why. Whereas all the various chemical reactions accelerate with rising temperature, each reaction accelerates at a different rate, causing undesirable changes. For example, heat causes the solids (tannin and colour) to drop out at higher rates than the sugars and acids are reacting, causing an imbalance. So, relying on shorter cellaring times is NOT a solution.On the other end of the scale, wines stored at very low temperatures will age much slower.
Although they may not be damaged from a temperature standpoint (as long as it is above freezing), these wines are commonly subject to the damaging effects of low humidity levels and temperature fluctuations usually associated with these environments (i.e. the refrigerator). As long as the humidity level is high enough (i.e. >50%) to maintain cork integrity, and temperature fluctuations are avoided, low temperatures should only slow down the aging process.
Discover how to protect your wine and allow it to age the way the winemaker intended in Chris Miley's WINE CELLAR SECRETS, this new e-book is a good place to start and learn
How To Build Your Own Wine Cellar.
