Wine Storage Factors, Simply Explained

It’s sad to see how many websites perpetuate myths about wine storage just to convince consumers that only the most expensive wine coolers/cellars/fridges can prevent fine wines from turning to vinegar overnight.  Unfortunately, the truth is far less motivating.  Below we discuss the basics of typical wine storage – i.e., wine held for personal consumption rather than speculation – and to help clear up some of the rampant confusion so new enthusiasts can make sensible, cost-effective buying decisions.

Terminology – Wine Coolers, Fridges, Cellars, Etc.

Wine Cooler vs. Wine Cellar - What's the Difference?We see lots of blogs and other websites that attempt to define and separately categorize wine coolers, wine cellars, and wine refrigerators – as if they can be systematically differentiated.  In most cases, however, you will notice that despite saying and assuming that they are distinct, the author can’t actually articulate any meaningful way to distinguish them.  And when the do, most websites attempt to categorize wine “cellars” based on vague notions of price class, by calling them “high-end” wine coolers.  That defines nothing, since prices vary along a continuum.

In other cases, the attempted distinction is more concrete but just as arbitrary – e.g., some say wine cellars must have humidity control.  But this is also not helpful, since even the most basic wine fridges can come with, or be fitted with, some form of humidity control system, such as a simple tray of water.  Finally, a third so-called definition that we typically see is that wine cellars are supposedly designed for more “long term” storage.  But this too is impossibly vague and unhelpful, since most wine coolers/fridges are designed to maintain proper long term storage temperatures.  So as long as the fridge or cooler holds up over the long term, then it can function for long term storage.  There’s no fundamental difference as to how they go about maintaining temperatures, since cheaper wine fridges and expensive “cellars” alike all use the same types of cooling machinery (compressors or thermoelectric systems).

Simply put, wine coolers, wine fridges, wine cellars or any other temperature-controlled boxes/cabinets are all designed to do the same thing:  maintain wine at optimal storage temperatures, generally around 55 degrees Fahrenheit.  Some can also chill whites to their proper service temperature (but that has nothing to do with storage).  Of course, these units may vary greatly in their reliability and quality, but this generally has nothing to do with whether they are marketed as wine cellars versus wine coolers.

Please note that when we talk about long term storage, for most consumers, this normally means up to five years, typically much less.  So if your fridge/cooler/cellar can function properly and reliably during this period, it can by this definition store wine “long term.”  If you plan on storing wine longer than this, and your cooler/cellar has been running well so far, go for it.  However, if you are storing fine wine as an investment, or are keeping ultra-expensive wine that you are passionate about, forget about storing your own wine altogether – put your best wine in a professional storage facility and only keep in your cooler the wine you intend to consume!

Maintain Proper Wine Storage Temperature

55F - The Ideal Wine Storage TemperatureThere is no question that temperature is the most crucial storage consideration of them all.  But the decision as to which temperature is best couldn’t be simpler, and we are stunned by all of the misinformation that exists.

Store All of Your Wine at Around 55 Degrees Fahrenheit

The consensus among the most respected wine organizations is that the best storage temperature – for both red and white wines – is around 55 degrees Fahrenheit.  That’s it!  And no you don’t have to maintain this temperature exactly, a few degrees above or below this is fine.  Don’t make the rookie mistake of confusing storage temperature with service temperature, which does differ between reds and whites!

General Recommended Wine Service Temperatures:

F

   Wine Type

64

   Red (Full-Bodied)

59

   Red (Medium-Bodied)

55

   Red (Light-Bodied)

54

   White (Full-Bodied)

52

   White (Medium-Bodied)

50

   White (Light-Bodied)

48

   Sparkling

Precision is Not Required

Moreover, there is no harm in storing wine colder than this, all this does is slow down maturation.  So why 55F?  Pretty much all of the credible sources agree that at around 55F fine wine (i.e., those wines that are worth aging and can benefit from aging) can slowly and gradually mature (oxidize) at a rate that improves and deepens the wine’s taste and aroma.  Much below 55F, the chemical reactions responsible for this process (like all chemical reactions) slow down or halt, thus lengthening the time needed for the wine to reach its “peak.”  So a wine that may require 5 years of aging at 55F to taste/smell its best may still not be ripe after 10 years in cooler storage.  On the other hand, if wine is kept slightly warmer than 55F, it will mature more quickly.  For example, a wine that might peak at 8 years may peak at 5 if kept closer to 60F.  Indeed, this is not a problem for most people – and many people might prefer speeding up maturation to some degree – which is why we are always surprised at how much paranoia exists with respect to temperature.

Temperature Stability is Most Important

Wine Storage Temperature - Stability is Critical!While storing wine anywhere within a few degrees of 55F is ideal, the bigger concern is maintaining stable temperatures around the chosen set point.  Why?  First off, a significant, prolonged spike in temperature is damaging simply because it rapidly promotes oxidation in a way that is not controlled and that can set off other, undesirable reactions, which can then affect the aroma and taste of the wine. However, much less dramatic but periodic temperature swings can be equally or more deleterious.

Wine, and particularly the ullage (airspace/unfilled space in the bottle), expands when temperatures rise and contracts when temperatures drop.  And because corks are porous, this essentially causes the bottle to “exhale” through the cork when temperatures push upwards and “inhale” as they come back down. In other words, some gas from the ullage is pushed out and fresh air is pulled back into the bottle during significant temperature swings.  This fresh air, unlike the original gas composition of the ullage, has a fresh supply of oxygen – and more oxygen means higher rates of oxidation.  As a result, a continuous cycle of excessive “breathing” can quickly degrade wine by over-maturation just as surely as continuous storage in elevated temperatures can.  Again, you don’t need to panic over a swing of a few degrees; however, the more stable you can keep your wines around the set temperature, the better.  Try keeping your wine cooler full – a larger volume of wine in the cabinet results in greater thermal inertia, which helps minimize temperature swings due to fluctuating external temperatures.

Maintain Proper Humidity

Wine Storage - Maintain Proper Humidity Levels

“23.3 degrees” by Claudio Matsuoka under CC BY 2.0

Humidity levels are important for wine stored for longer periods, for a couple reasons.  First, low humidity can cause corks to shrink, which sacrifices their sealing ability and can allow outside air to infiltrate and/or wine to be pushed past the cork.  And sealing failures can expose the wine to higher levels of oxygen, which can over-mature the wine or spoil it depending on the magnitude of the breach.  Second, high humidity can foster the growth of molds and mildew, which is not so much a problem for the wine as it is for the wine’s labels, which can be permanently discolored and lower the bottle’s potential resale value.

Most wine storage experts suggest keeping your collection at around 70-75 percent humidity to ensure good cork sealing without promoting mold growth.  However, as with most figures, precision is not necessary, and anything from 50 – 80 percent is probably just fine.  Again, keep things within reason.  If your wines are valuable enough to be concerned about label damage and resale value, they should be sitting in a professional storage facility anyway.

Protection From UV Light

The damage to a wine’s taste/aroma that can occur from exposure to UV light is well documented.  UV (ultraviolet) light is a form of high-energy invisible electromagnetic radiation present in natural sunlight and artificial light sources to varying degrees.  Most people recognize the effects of UV exposure in the form of suntans and sunburns.

As far as wine is concerned, however, it’s believed that UV radiation reacts with sulphur compounds that naturally occur in wine, causing a “light strike” reaction – a process whereby these compounds are then broken down into to smaller, undesirable metabolites that go on to form unpleasant volatile compounds, which even an average palate can notice at trace levels.  Indeed, the regrettable flavors/aromas associated with such compounds, such as dimethyldisulphide and hydrogen sulfide, have been characterized by test subjects as “wet dog” and “cooked cabbage.”  See the problem?

Moreover, it is evident that even artificial lights, especially florescent lighting, emits enough UV to do damage – and quickly.  In fact, one study found that white wine stored in clear or green-colored bottles (which filter very little UV light) under typical grocery-store florescent shop lighting suffered from “light struck” poor flavor with just hours of exposure.

Dark Wines Have Greater Protection From UV light

“Casa Mateus grape vines” by Bernt Rostad under CC BY 2.0

Interestingly, not all wines are equally sensitive to UV light.  Tannins, which are present in virtually all wines, are a class of very powerful phenolic compounds, and these compounds help to reduce the effect of “light struck flavor” in UV-exposed wine.  Tannins are present in the highest concentrations in dark-colored grape skins.  White wine, made with light-skinned grapes, has much less tannin, and therefore has less much less protection from a similar period of UV exposure than a red wine.  This is analogous to the greater risk of sunburn light-skinned people face due to their relative lack of UV-protecting melanin.

Now the good news is that wines stored in opaque or amber-colored bottles are very well-protected from UV light, as compared to green bottles, or the worst – clear bottles, which offer little to no UV protection.  In addition, most wine coolers/cellars today use UV-free LED interior lighting and tinted door glass that further minimizes the risk of UV degradation.  So, assuming you don’t buy wine in green or clear bottles, and are storing your collection in a dim location or within a typical wine cooler, you have nothing to worry about.

Avoid Vibration, Within Reason

Wine Storage & Vibration

Seismograph, San Juan Bautista Mission” by Ray Bouknight under CC BY 2.0

Of all of the storage factors, we see some of the most unsupported fear-mongering focused on the issue of vibration.  Some sites will lead you to believe that even the vibration caused by a compressor turning on/off in the wine cooler can over-ripen or somehow damage your wine, and that as a result only thermoelectric coolers are acceptable.  This is hogwash, to put it politely.

Yes, shaking, excessive handling, or otherwise subjecting wine to repeated, significant vibrations that are sufficient to actually stir or agitate the contents can theoretically speed up oxidation and lead to premature aging, but that is not what we are talking about.  Unless you live over a subway system, under a landing strip, or host rock concerts/dance competitions near your wine cooler, relax, and just keep your collection in a quiet place and away from heavy foot traffic.

Store Bottles on Their Side

Storing Wine on Its Side is Efficient & Good for Corks

Wine Rack” by R4vi under CC BY-SA 2.0

 

Why do you always see wine bottles laid on their side?  In addition to being a great way to make the most out of your cellar space, the general wisdom is that storing bottles horizontally brings the wine in contact with the cork, which in turn keeps the cork moist and sealing properly.  This may not be necessary for sparkling wines and Champagne, however, as the internal gas pressure supposedly keeps the corks moist enough while the bottles remain upright.

Featured (top) photo credit: “Cellar” by Stewart Butterfield under CC BY 2.0

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