Cellaring wine - an acceptable margin of error

Rarely do I plan these articles and stories; the motivation tends to materialize without warning - and this latest tale of exploration is no exception. 

During an impromptu visit with friends in the city, I found myself standing in their wine cellar for a tour and discussion of bottle storage.  I never decline the opportunity to visit a cellar; big or small, modern or old, be it adorned with custom cabinetry or plastic milk cartons, I am enthralled by the storage techniques that people employ for their personal collection of treasured bottles.

The home and subject of this discussion is stunningly tasteful, decorated in a mix of modern, classical, and Victorian styles.  Care and well-thought planning have obviously gone into every square foot of this 130-year-old home nestled in the heart of the Toronto’s historic Annex district.  As the ladies venture in the one direction for a walk-about of the couples' latest and extensive renovations upstairs, the gentlemen make their way below ground level for a conversation on wine preservation. 

Tiled floors accent a clean line of white cabinetry at the base of the stairs as we make our way toward a half-lit thermal door installed between the basement living area and the wine cellar itself. Opening the door reveals a cold storage room now tastefully converted with wooden bottle racking that stands approximately five feet high spanning the width of the area. We casually chat about the old foundation, its exposure to the sun, and the grade level outside the sunken window.  To my surprise, the owner recalls a natural earth floor beneath what is now a clean concrete slab.  ‘Dirt in a wine cellar is a magical thing’ and in hindsight, my host is well aware that given the option, to pour concrete – or any other sealed product over the natural surface, is likely a planning oversight.  A natural floor maintains a balance within the cellar by slowly adding to and removing humidity from the air while preserving the cool cavernous climate.  You might wish to weigh the pros and cons carefully before covering up such a modest luxury.  Most wine enthusiasts can only dream of dirt-under-foot and must opt instead for a climate controlled room to house their best bottles. If you fall into this group, there are several custom cellar contractors that are certainly worth looking up.

The collection today is a tasteful mix of the old world and new.  A hundred bottles of French, Spanish, and Italian labels plus a selection of North American wines catch my eye as I glance across the symmetrical racks. Several examples are now ready to drink; others do not require aging, while a select few will certainly benefit from additional time on their sides.  In essence, this well-planned cellar will serve a wide range of entertainment needs for many years.

As we chat, I can't help but notice and inquire about a large dehumidifier, coiled hose, and extension cord pushed off the side of the small room.  The explanation I receive for the presence of this equipment is the reason for this post.

"A wine expert friend," my host recalls, "says that a cellar must remain at 60% relative humidity and the temperature held at a constant 14˚C."

There are two ways to address a statement like this.  The first is to say nothing in response; this collection of wine is in good hands and will certainly mature without concern or fault.  The other train of thought is to off-load this dedicated enthusiast who is obviously on the right track but has unknowingly placed undue concern upon a concept that was mastered long before the invention of vapour barriers, weather-stripping, and supplemental climate control.

Let us first touch on humidity: in terms of a bottle's evolution, there is no ‘maximum’ level of humidly.  You cannot harm a bottle of wine by storing it in an excessively humid location.  Levels above 80% will eventually cause discolouration of the labels but no harm will ever come to the contents of the bottle, provided the cork does its job.  The possibility of mould development in your home as a result is another subject that I won’t touch in this discussion. At the opposite end of the humidity spectrum, bottle storage in a very dry location for anything greater than six months will eventually result in the failure of the cork's seal.  Stelven closures (screw caps) are immune to the effects of humidity. Bottles sealed under natural cork however, should remain ideally within the range of 55 - 75%.

The use of a dehumidifier in your cellar is nothing short of inconvenient.  Not only does the unit require daily attention if direct drainage is not possible, but the machine itself generates constant heat while running.  Should your cellar environment also necessitate some form of supplemental cooling, that system must now work even harder to maintain an ideal temperature.

On the subject of temperature, the ideal range for a wine cellar is 11-13˚C / 52-55˚F. Any warmer and the wine will simply evolve faster – arguably with less style and grace. The colder end of the spectrum slows the essential physical transformation, eventually stunting the bottle’s development completely as you encroach on the freezing mark. The need to respect temperature is frequently misunderstood and I will reiterate that seasonable changes that occur gradually over several weeks are of no concern whatsoever.  Rapid changes, on the other hand, are your bottles’ worse enemy.  An example might be a sudden spike, to say 20˚ degrees on a hot day, plummeting again to 10 or 12˚ overnight.  The contents of the bottles will expand and contract in response to the environmental changes, but the silent victim in each case is the cork, as it struggles to maintain the airtight seal against its glass-walled neighbour. Eventually the elasticity of the stopper will succumb to the constant state of flux and the wine may seep from the bottle. Of greater concern is that oxygen may in turn replace the evaporated contents.

In an ongoing effort to relieve some of the stress associated with buying, storing, and consuming fine wine, I would like to summarize the idea of storage by stating that if you plan to drink your wine in the next 30 days, store it wherever you like (within reason).  If you buy by the case but intend to consume within six months to a year, don't sweat the small stuff. Keep these bottles in a cool, dark location and enjoy them at your leisure.  Better bottles purchased for long-term storage do need an extra element of care:  lay these bottles on their side, in a place where they can evolve without interruption.  Follow the temperature and humidity guidelines above while recognizing the need for a dark, odourless, and vibration-free environment as well.  This will greatly increase the potential for enjoyment as you open these old treasures many years later.

Should you still feel that cellaring wine necessitates the need for laboratory-like conditions, I invite you to entertain the thought of how wine was stored only 50 years ago.  If you are still unconvinced, I’ll invite you to my place for dinner and pour you a 15-year-old bottle that has witnessed more storage sins than I care to admit.  My gradually fluctuating cobweb-crusted stone cavern has yet to disappoint.

For more information on wine cellaring see also:  An Investment in Taste