That certain wines must be aged to achieve peak quality is so pervasive in the general public's consciousness that it can be considered common knowledge. Most people also know that wine must be stored in a certain manner. Few people know the details, nor understand the actual science behind aging wine, which may explain why so many people underestimate the importance of proper wine storage .
Even so, maturing or aging wine is both a science and an art. A science, in that chemistry is the engine that drives the whole process. The individual reactions involved are well understood, predicable and clearly illustrate why proper storage is so important. But it's also an art. Wine composition is so diverse and complex that we're talking about a lot of different reactions . So it can be extremely difficult to exactly predict the end result that aging will have on the different wines. It can be just as tough to predict results among different vintages of the same wine (though vintage charts help). Even experienced enologists with proper cellars are not always successful in their pursuit of creating the perfect tasting wine. To complicate matters more, taste is subjective. Some people like their wines aged (for their secondary flavours), and some don’t (they prefer primary fruit flavours).
Luckily for us, there are enough impatient collectors around willing to sacrifice a bottle to see how a wine is developing. Assuming you were also around to taste it, and you had the same wine in your cellar, you're in luck. Otherwise we must rely on the advice of wine experts. Most of the wines you now have in your cellar are being sampled just about every year by one expert or another. Hence we rely on their advice and council.
Despite the expert's advice, we are sometimes disappointed. If your wines were stored improperly, well the reason is obvious. They are likely sampling wines that have been well cared for. But even if your wines were stored properly, your bottle still grew up in a slightly different environment than the one sampled. For example, how was it treated during its trip between the winery and your cellar. I've seen how some wines are transported, and it's painful to watch. Hence, your bottle likely underwent slightly different chemical reactions than the one sampled by the wine expert. What happened before it landed in your cellar - out of your control. So luck also plays an important role. This may help explain the mysterious allure of wine. There are no guarantees when it comes to aging wine. We have all been pleasantly surprised by wine that should not have improved with age (but did), and vice versa.
Although science explains the need for proper storage, and wine experts and collectors around the world confirm it, many collectors continue to cut corners. Why is that? Partial blame lies in the fact that we have all enjoyed some pretty good wine that grew up in some pretty bad neighborhoods. Luck? Maybe. But most of us don't taste wine for a living (or sample 100's of wines a week), so we tend to take note only when something has actually turned or spoiled. The negative effects of improper storage cannot be avoided. Over time, poor storage will always have an effect on the wine's flavour and/or bouquet. Sometimes the difference is subtle (and for some of us… too subtle). At other times, it can be very pronounced. But even drastic changes may go unnoticed. Our taste buds have weak memories, and unless you have a sample of properly stored wine on hand to compare, often it's a case of: “you don't know what you are missing”.
So what is proper storage? First, let's look at the basics. All wine is perishable. Unlike whiskey, there is insufficient alcohol in wine to preserve it indefinitely. All wines will go bad over time. Even wines like Sauternes (some of which will continue to improve over a 100 years) will eventually taste lousy. Age-worthy wines may degrade in less than a year if not properly maintained. “Ready to drink” wines have a “best before” date that can be measured in terms of months, and less when stored in conditions of undue stress. All wines will be history in mere hours if left in the truck of your car on a hot summer's day.
Actual storage requirements are a function of the type of wine, and its intended use. Clearly, fine wine destined for 5+ years of storage and eventual consumption by a reasonably experienced wine drinker requires much stricter control than a bottle of Table Wine destined for next month's spaghetti sauce.
Storage Needs for the Average Wine Drinker
At the risk of losing potential customers, let's be frank. The vast majority of wine out there today (95%?) is “ready-to-drink”. Manufactured for immediate consumption, they will NOT improve with time. In fact they will start to degrade from the day they're corked - even if properly cellared. Proper cellaring will maintain your “ready-to-drink” wines much longer, but it will not improve them.
Someone once did a study of all the wine purchased from the LCBO shelves, and determined that the average length of “cellaring time” for all wines sold was something in the neighborhood of 14 hours! Producers know this, and develop most of their wines for this purpose. In general it is far less expensive to make “ready-to-drink” wine, so why not?
Not to say that “ready-to-drink” wine means low quality – far from it. There are very high quality and very expensive “ready to drink” wines (and grape types) that are simply not designed to be age-worthy. (i.e. The pot roast tastes great on the 5th day, but the leftover trout will not). Bottom line: if kept for only short periods, (i.e. few months) specialized storage is not an issue for the average wine drinker, the average wine, or any wine for that matter.
Most “ready-to-drink” wines can be safely stored up to 8 or 12 months or so without significant loss of quality as long as it is kept in an area with the following minimum conditions:
• away from direct sunlight,
• between of 4ºC and 18ºC (40ºF and 65ºF),
• temperature does not fluctuate more than about 2 to 3ºC (5ºF) - at least not too frequently?! and
• relative humidity levels are greater than 50%.
Store it outside of these limits, and all wine is subject to passing their prime or spoiling in just a few months. Although the first two conditions can be easy to provide (if you have a basement), most people find it very difficult to provide the last two without some type of cellar or wine cabinet. So drink up folks, or better yet, call us!
Storage Needs of the Collector & Enthusiast
Enthusiasts and collectors have a more serious storage need. They maintain large and/or valuable collections. Due to the sheer size of some of these collections, even their “ready-to-drink” wine tends to go unopened for longer periods. Plus, the collector/enthusiast usually participates in premium age-worthy wines. These wines will actually improve with age and may only reach their full potential after 5, 10 and up to 50 years in the bottle. But only if properly cellared! With the negative consequences of improper storage increasing with time, proper storage is a pre-requisite for this type of product.
Storing and Aging Fine Wines
In order to better understand the concept of preserving and aging fine wines, we take a closer look at the six critical elements associated with proper wine storage:
- temperature stability
The ideal temperature for wine storage is somewhere between 11ºC and 14ºC (52ºF to 58ºF). Note that there is an acceptable temperature range - but once chosen, temperature must not fluctuate.
Wine is a complex and fragile balance of amino acids, phenols, carbohydrates and other chemical compounds. Aging wine is a series of different chemical reactions between these compounds and minute quantities of oxygen in the bottle from when it was corked, plus minute amounts allowed to enter through the cork over time. These reactions are easily affected by physical and chemical changes taking place in the environment, particularly temperature. Since the speed of the average chemical reaction increases with temperature (the rate doubles for every 10ºC increase in temperature), wine hardly ages at all if stored below about 10ºC (50ºF). Store it at 25ºC (78ºF), and an age worthy wine that would normally require ten years of careful aging, may be past its prime in just a few months.
Now some of you may be thinking, “Why not just store wine in my closet? It's warmer, it will 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. Period. And here's why. Whereas all the various chemical reactions I mentioned will “accelerate” with rising temperature, each reaction “accelerates at a different rate” . This causes 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, storing at higher temperatures to shorten 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 as damaged as those stored at higher than ideal temperatures (as long as it is above freezing), these wines are commonly subject to the damaging effects of low humidity levels that are usually associated with cold environments (i.e. the refrigerator is probably the number one worst place to store your wines). As long as the humidity level is high enough (i.e. >60%) to maintain cork integrity, and temperature fluctuations are avoided, lower than ideal temperatures for a portion of the wine's life should only slow down the aging process.
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 to 3ºC (5ºF) around the average once per year.
Temperature stability is the “holy grail” of wine storage. Besides humidity, it is the most important of the storage requirements, and at the same time one of the hardest ones to achieve. Maintaining constant temperature over time is even more important than the actual average temperature level. I haven't tested it, but my gut feeling is that a wine would be “less damaged” if stored at a temperature outside the range (say 64°F) provided the temperature was constant, than one stored at more ideal temperatures that “fluctuate dramatically within the range” (e.g. temperature fluctuates daily between 51°F and 58°F). For those using home storage methods, a 2 to 3ºC ( 5ºF) temperature variation can be a daily occurrence. I wouldn't try cellaring wines more than a year or so in those conditions.
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. Most don't have a Max-Min function, so you will have to look around for this. Make sure you use a liquid probe, like the ones used to measure wine temperature for serving. Liquid temperature is what counts, not the air temperature. Fluctuations in air temperature, even dramatic ones, will have no effect on your wines provided they are short lived. This is due to the thermal insulating properties of the glass bottle, and liquid in general. But if the air temperature in your storage area is at one level all night, and at another all day (or changes from season to season) - that is when you will get into problems.
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/wine will seep 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 evaporating wine. This leads to the low fill level or ullage seen in older wines, and the oxidized flavor of others.
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 lose 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 if they occur on a daily basis.
Relative humidity levels should range between 60 and 80 percent.
Cork is a natural product and will deteriorate with time. And yes, the cork will still dry out even when the bottle is placed on its side. Although the bottom of the cork is in contact with the wine, the top of the cork is exposed to the air and influenced entirely by the conditions of the air around it. If the air is too dry, the top of the cork will dry out, shrink, crack and allow more air to come into contact with the wine. The problem is made worse if low humidity is accompanied by temperature fluctuations. In this climatic zone (i.e. Toronto), low wintertime humidity levels ruin a lot of corks/wines. The damage won't happen overnight. It takes some time. How many seasons? Impossible to predict. It really depends on the particulars of each and every cork.
High humidity levels will help keep the cork from drying out. Humidity below about 50% RH is getting too dry. Levels above 80% will not damage the cork/wine, but you run the risk of mold or mildew damaging your storage area and your wine labels.
Wine needs to be kept in an odour-free environment.
Since some air will always get back into the wine through the cork, the molecules that make up that odour can, and will, get into the wine over time (i.e. we're talking years here, not from simply painting the house). Certain odours are fairly benign. Others like highly volatile chemical compounds are particularly harmful. Odours to look out for include solvents (i.e. fresh paint, cleaning solutions), or various aromatic food products like onions, garlic, etc. Don't store these around your wines.
Wine should not be subjected to excessive amounts of light.
Light, especially the short wavelengths, breaks down the complex molecules that create some of the special flavours in properly aged wines. This is rarely a problem since wine is already well protected in glass that virtually absorbs all ultraviolet rays. Dark-coloured glass absorbs most other light. Low-level lighting will not harm wine. But please, keep out of direct sunlight!
Although not an environmental condition, security is an important issue. There is no sense having a sophisticated cellar if your wine is susceptible to loss or damage due to fire, theft, or equipment failure.
Collectors and enthusiasts invest a lot of time and money in their wines. Even fairly modest collections can be valued at $100,000+, yet their owners rely on home security systems that may not be particularly effective against the professional thief. Luckily most thieves are too lazy to lug out a lot of wine, so you may not be hit too hard. You're crazy uncle or teenage children might be a greater threat. Using economies of scale, the professional wine storage facility can afford to install professional, commercial grade security equipment with sophisticated back-up systems to protect your wines.
Home wine collections are more susceptible to damage by fire. Houses don't have sprinkler systems. If there is a fire, the prognosis is usually not good. Professional storage facilities protect their inventory with commercial-grade fire suppression equipment such as the sprinkler system. These systems rarely let a fire get out of control.
Residential wine collections are most susceptible to loss or damage due to equipment failure. Despite investing vast sums of money into their home storage systems, few install any redundancy into the system. If something breaks, the cellar is down until the problem is fixed – and thus the temperature fluctuations start. Worse yet, something could go down while the owner is away. Collectors have returned from vacation to find their collections fried or frozen solid.
A Note on Vibrations
The jury is still out regarding the effect of vibrations on wine. Some purists insist that vibrations affect flavour and bouquet. This is certainly true at the “drinking stage” – all old reds need a few days to rest quietly (in an upright position) to allow the bitter sediment to settle. But there really is no clear evidence (that I know of) that suggests this is as an important issue during the storage stage - provided the vibrations are not extraordinarily strong and persistent.