The Basics of Wine Storage

That certain wines must be aged to achieve peak quality is perhaps so pervasive in the general public's consciousness that it can be considered common knowledge. Many people also know that wine must be stored in a certain manner, though few can recite the details. Still fewer understand the actual science behind aging wine, which may explain why so many people underestimate the importance of proper wine storage.

Storage or aging wine is both a science and an art. It is a science in that chemistry is the engine that drives the whole aging process. The reactions involved are well understood, predicable and clearly illustrate why proper storage is so important. But aging wine is also an art. Wine composition is diverse and complex and it can be extremely difficult to predict the end result that aging will have on any particular brand. It's just as tough to predict results among different vintages of the same brand (That is why there are vintage charts.) Even experienced enologists with proper cellars are not always successful.
storing/aging wine

winebarrels.jpgSo luck also plays an important role, which 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 never have improved with age (but did), and vice versa.

Although science explains the need for proper storage, and wine experts 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. But we tend to take note only when something has actually turned or spoiled. Thankfully, this is still fairly rare, especially in our temperate climate. But 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 a bottle of whiskey, there is insufficient alcohol in wine to prevent it from going bad over time. Most wines have a "best before" date that can be measured in terms of months and less when stored in conditions of undue stress. Even age worthy wines, wines that will improve with age, may degrade in less than a year if not maintained properly.

Storage requirements are a function of the type of wine, and its intended use. Fine wine destined for 2+ years of storage and eventual consumption by an experienced wine drinker requires much stricter control than a bottle of table wine destined for next month's spaghetti sauce.

Storage Needs of the Average Wine Drinker
At the risk of losing potential customers, let's be frank. The vast majority of wine out there today is "ready-to-drink". They're manufactured for immediate consumption and will not improve significantly with time. Someone once did a study of wine purchased from the LCBO, and determined that the "average" length of time in "storage" for this wine was something in the neighborhood of 14 hours. If kept for only short periods, specialized storage is not an issue for average wine (or any wine for that matter).
 

Even "ready-to-drink" wines can be safely stored for up to 8-12 months without any loss of quality as long as it is kept in an area with the following minimum conditions:

  • Away from direct sunlight
  • Temperatures between of 4ºC and 18ºC (40ºF and 65ºF)
  • Temperature does not fluctuate more than 2-3ºC (5ºF) once annually,
  • 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 are easy, 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 Enthusiast & Collector
Enthusiasts and collectors of premium wine have more serious storage needs. They maintain large and/or valuable collections. Due to the sheer size of some of the collections, even "ready-to-drink" wine tends to go unopened for long periods. With the negative consequences of improper storage increasing with time, all the wine is susceptible if not stored properly.

The collector/enthusiast also participates in premium age-worthy wines. These wines improve with age and may only reach their full potential after 5, 10 and up to 25 years in the bottle. Proper storage is a pre-requisite for this type of product.

Storing and Aging Premium Fine Wine
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-average
  • Temperature-stability
  • Humidity
  • Ventilation
  • Darkness
  • Security

Average Temperature
The ideal temperature for wine storage is 13ºC to 14ºC (55ºF to 57ºF).

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 the minute quantities of oxygen allowed into the bottle through the cork. These reactions are easily affected by physical and chemical changes taking place in the environment. 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). Place it at 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 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. Period. 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.

Temperature Stability
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.

Humidity
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.

Ventilation
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. Highly volatile chemical compounds are particularly harmful. Some odours to look out for include solvents (i.e. fresh paint, cleaning solutions), or various aromatic food products like onions, garlic, etc.

Darkness
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.

Security
Although not an environmental condition, the issue of security is an important one. There is no sense having a sophisticated cellar if your wine is susceptible to loss or damage due to fire, theft, and equipment failure.

Collectors and enthusiasts invest a lot of time and money in their collections. Even modest collections can be valued at $50,000+, yet their owners rely on home security systems that may not be particularly effective against the professional thief. Using economies of scale, wine storage facilities can afford to install professional, commercial grade security equipment with sophisticated back-up systems.

Residential wine collections are also susceptible to loss or damage due to equipment failure. People invest vast sums of money into their home storage systems when in fact there is zero redundancy built into the system. If something breaks, the cellar is down until the problem is fixed. Worse yet, something could beak while the owner is away. Collectors have returned from vacation to find their collections fried or frozen solid.

Home wine collections are also more susceptible to damage by fire. Most professional storage facilities offer added protection against damage by fire with commercial-grade fire suppression equipment such as the sprinkler system.

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. But there really is no clear evidence that suggest that this is an important issue for wines, even for those that do throw off a sediment. Letting the wine sit in a quiet area for a few weeks before serving (like one should do with all older reds) will allow the bitter sediment to settle.