Cellar Temperature

I recently responded to Robin Garr's query on storing wine in the refrigerator, and I wanted to poll the group on a related question...

Was 55 degrees accepted as the "optimum cellar temperature" just because that is the normal, consistent temperature in a cave, OR has there ever been any long-tern studies on how well wine fares at various <b>consistent</b> temperatures?

For example, place a case of the same wines in different controlled environments (say, 45, 55, 65 & 75 degrees). After the 5th year, start tasting a bottle a year from each environment. and compare & rate the wines.

With more wines & space, you could even test with a case each of a dozen different varieties in each environement...

Yes, it would take 10 to 15 years to understand the results, but the knowledge would benefit everyone else who follows...

Reminds me of a WSJ column where Dottie & John "found" a case of inexpensive wines they had "lost in a closet" for 10 years -- their conclusions were interesting!

Cheers!
Todd
http://www.HDLEnhancement.com

Welcome, Todd -- it's good to see you here.

I've puzzled over the basis of the temperature/humidity reccos ever since I started studying wine seriously. My own best guess is that 55F was the temperature of London cellars.

Whatever the real history, here's an interesting article on the subject from Harpers written by Jamie Goode.

Regards, Bob

BTW: your website loads wonderfully fast since I last visited. Well done. B.

Was 55 degrees accepted as the "optimum cellar temperature" just because that is the normal, consistent temperature in a cave, OR has there ever been any long-tern studies on how well wine fares at various <b>consistent</b> temperatures?

I've spent a few moments contemplating this myself. One thought is that cave temperature was a given before climate control was introduced. Winemaking perhaps accommodated this given with its practices. This would then mean turning your statement on its head, i.e. certain winemaking and storage practices adapted and are viewed as ideal for the given, immutable cave temperature. (All very Darwinian, I know.)

Now, as you suggest, perhaps other temperatures might be better for storing wine. I'd like to hear the results of related studies myself.

Todd, welcome. Neat website!!

Bob R, thanks for posting Jamie`s article.

"One thought is that cave temperature was a given before climate control was introduced. Winemaking perhaps accommodated this given with its practices."

Gary, Robin made the same point to me tonight personally. There's a great deal of support for your position. Ground temperatures are an important factor in heating and cooling systems using geoexchange principles. It appears that the average ground temperature at depths between 30 to 150 feet in Europe is about 55 degrees F. (At these depths, temps vary no more than an average of 2 to 5 degrees F over the course of the year.) There are many sources of information on the web -- this short excerpt is a good summary of the principles.

In the UK the ground temperature at depths between 10 to 50 metres average around 12°C. In the soil layers above 10m, the ground temperature will vary dependent upon weather conditions - the temperature will reduce towards the surface during winter months and will increase during the summer. Below 50m depth the ground temperature begins to rise with depth at a rate about 3°C per 100m. The consistency of the ground temperature is due to the fact that every square metre of the ground surface in Europe is irradiated by approximately 1100 kW of solar energy annually.

It looks like wine makers adapted to ground temps -- Darwin may rule after all!

Or, maybe it's another proof of the validity of Intelligence Design. In that interpretation, if I have it right, the average ground temp was designed exactly to age wine appropriately.

Regards, Bob

Bob & others,

I do dispute the fact that there is a uniform ground temperature thoughout all of Europe.

Afte all, Sicily or Andalucia on the one hand, Iceland or northern Sweden or Norway certainly do no get the same amount of 1100 kW of solar energy throughout the year, not to speak of mountainous regions. If this was true, then annual average temperature would be the same throughout Europe — which quite obviously is not the case.

But there is quite an obvious answer to the question of ground temperature. Below some 5 meters (15 feet) under ground the seasonal variation falls below ±1°C or ±2F. This is more or less accepted wisdom, and that's exact enough for our goals.

But what is the temperature down there? Quite obviously, the fundamentals laws of thermodynamics do apply also here: It's simply the annual average temperature at ground level!

So Champagne and Germany are at around 10°C, Vienna is at 10.5°C, Burgenland at 11°C. I've heard of Bordeaux being at 13°C, but that has not yet been confirmed. Burgundy should be soewhere around 11 to 12.

And this answers part of the original question: The regions I cited are those who make the longest-lived wines. Aged at their origin in deep enough cellars, this means 10 to 13°C.

I don't know about the average temperature of London, but from what I have read here, it's something like 12 to 13°C, which seems plausible.

If your cellar is too warm, there are two plans: either you move much further north, or you build a cellar in the mountains where average temperatures are lower.

I know that this is not the perfect answer to the original question, but it might be a useful piece of stone in assembling the mosaique.

"I do dispute the fact that there is a uniform ground temperature thoughout all of Europe."

Michael, the discussion has been "average" ground temperature within a relatively narrow range, not uniform ground temperature.

Caves might have to be a bit deeper in warmer areas and more shallow in reach that average -- assuming there is an "ideal" range.

For an example of how the geothermal folks approach the issue, 55F to 57F is often cited as the "average" ground temperature for the entire country. Geothermal systems are installed at a depth in the ground to create the appropriate difference in surface and ground temperature.

It would be interesting to find a survey of the actual temperatures in various natural cellars throughout Europe to see what temps wine makers use/used in practice before air conditioning was introduced. I haven't seen such a census -- have you?

Surely the answer if your cellar is too warm is to dig deeper!

If a stable temperature of 12/13°C is not reached until the band of earth 10 to 50 metres below the surface, that implies that the ceiling of the cellar needs to be deeper than 10 metres.

I think that there are very few domestic cellars that meet that criterion, even in old European houses. Typical, I guess, are and always have been cellars like mine here in Belgium where the ceiling is less than 1 metre below the surface and the floor approximately 3 metres below.

Of course older houses often benefit from thicker walls which do help insulation; in my 30 year old cellar (i.e. quite modern) temperatures in a hot spell, like this year's July, can climb up to 22° and in a cold winter (rare nowadays) descend to 10°; right now the temperature is still 16° due to the record-breaking mild autumn.

Nevertheless some of my Bordeaux have been in the cellar for 30 years and good bottles are still drinking well, although the mildly unstable conditions may be increasing the incidence of ullage and therefore of "off" bottles. Also some friends with temperature controlled cellars claim that my older whites and champagnes are less fresh than theirs.

In the Bordeaux area, underground cellars are a rarity as I discovered when looking for a house. In most châteaux, the chai is at ground level albeit with thick walls. I was told that the summer temperature in the famous round chai at Château Lafite is ususally 18° and that was before 2003. Nevertheless some of the old bottles kept by châteaux are said to be more that satisfactory!

There seems to be little doubt on the basis of experience that the conventional wisdom about the ideal of a constant 12/13°C (approx 55°F) is correct for a normal lifespan. Nevertheless lower temperatures can benefit one's heirs (e.g. the reputedly incredible condition of wines from the very and cold damp cellars at Glamis Castle) and moderately higher average temperatures with quite a wide fluctuation are far from catastrophic.

One issue in Jamie Goode's otherwise excellent article, which is open to dispute, concerns the effect of light. A few years ago la Revue du Vin de France reported on a long term experiment on cellaring conditions. Their conclusions on temperature and humidity conformed to conventional wisdom. However they concluded that exposure to light has a quite rapidly harmful effect, particularly on white wines is clear bottles. That is why I never by bottles illuminated by spot lights - a bad practice sometimes found in otherwise serious wine stores!

[Jenise]

Todd, somebody, somewhere, has probably tested what you propose, but anecdotally isn't it safe to presume that the warmer the cellar the more accelerated the aging curve? To the point where, 55 degrees would be a good cellar temperature for someone in their 30's, but someone who starts collecting in their late 50's, say, and who has a penchant for long lived Bordeaux might be wiser to keep his cellar 5 or 10 degrees higher?

There are a range of opporunities between suspended animation on the low end and possibly harmful at the upper end. Or to put it differently, if you want to preserve very old wines as pristeenly as possible or keep all wines you own such that your heirs can enjoy or sell them at top dollar is one version of "ideal", and to have them safely resting but ready for you to enjoy during your lifetime could be another.

We contemplated all the above when we built our new cellar. It's at 60.

55 degrees would be a good cellar temperature for someone in their 30's, but someone who starts collecting in their late 50's, say, and who has a penchant for long lived Bordeaux might be wiser to keep his cellar 5 or 10 degrees higher?
We contemplated all the above when we built our new cellar. It's at 60.

I have also thought it reasonably well accepted that bumping it up a few degrees probably speeds the maturation process. I guess the question is whether it matures AS WELL when it matures faster. I suspect that it affects different wines differently, such that some wines may mature just as well, but faster, at 65 than at 56, but others don't mature as well.
All that said, at my age (the O stands for Old) I have my cellar set at 62 degrees. And in five years, I'll probably bump it up a few more.

...I suspect that it affects different wines differently, such that some wines may mature just as well, but faster, at 65 than at 56, but others don't mature as well.
All that said, at my age (the O stands for Old) I have my cellar set at 62 degrees. And in five years, I'll probably bump it up a few more.

Why not just maintain your cellar temp equal to your age?

[Jenise]

I guess the question is whether it matures AS WELL when it matures faster

Oh I think the evidence is in that longer/slower=always better. It's just that what's better for the wine might not fit your personal timetable!

Why not just maintain your cellar temp equal to your age?

My initial reaction is that at age and temperature 85, not much would survive. My second was, would I care?

You guYs are looking too deeply.

Temperature doesn't matter that much.

95% of all wine is consumed very young and hasn't had time to degrade from heat.

The other 5% will age at a speed dependent on temperature, but as long as the temp doesn't exceed around 21 C. (70 F.) the maturation won't be damaging, just faster. If you hit much above that the chemical changes will not just occur more quickly but will also vary in kind and result in an end product different from a more slowly matured sample.

Below that, the maturation process is pretty uniform, with the only variable being speed. The so-called standard cellar temp just represents a point at which wines will mature within a reasonable time. Keep wine down at 45 - 50 F (7 - 10 C) and development will be ...glacially slow. If you want to benefit your children and grandchildren, do it that way.

But here is an interesting idea. Treat extra cool storage as a suspended animation method. Put a wine that is really very good into very cool temperature now, and keep it there until another vintage, much younger, kept at higher temperature, reaches about the same point in development. When the curves cross, open them both and answer the question most people think would be impossible - which wine is actually better.

For instance - is the 1990 Montrose as good or better than the 1970 Montrose? That's how you can find out. Let us all know....

Another question is whether all wines mature optimally at the same temperature. 55F might be ideal for Cabernet Sauvignon, but 60F might be better for Syrah. Riesling might prefer 50F. I'm guessing that no one has looked into this. I've certainly never seen it addressed.

Another question is whether all wines mature optimally at the same temperature. 55F might be ideal for Cabernet Sauvignon, but 60F might be better for Syrah. Riesling might prefer 50F. I'm guessing that no one has looked into this. I've certainly never seen it addressed.

We are talking about chemical reactions here. Unless you have different chemicals in different wines (true, of course) which mature differently I don't see it making any difference.

It isn't impossible but I've never seen any evidence of this in the wine chemistry I've seen.

Surely the answer if your cellar is too warm is to dig deeper!

If a stable temperature of 12/13°C is not reached until the band of earth 10 to 50 metres below the surface, that implies that the ceiling of the cellar needs to be deeper than 10 metres.

Tim, digging deeper cannot overcome the principles of thermodynamics.

If the place where you live has an average annual temperature of 14°C, you will *never ever* reach 12°C, no matter how deep you dig.

Michael, surely for me in Belgium digging deeper would solve my problem as I suspect that the average temperature here is around 12°C? Of course buying a good air-con unit would be cheaper.

"I do dispute the fact that there is a uniform ground temperature thoughout all of Europe."

Michael, the discussion has been "average" ground temperature within a relatively narrow range, not uniform ground temperature.

Caves might have to be a bit deeper in warmer areas and more shallow in reach that average -- assuming there is an "ideal" range.

For an example of how the geothermal folks approach the issue, 55F to 57F is often cited as the "average" ground temperature for the entire country. Geothermal systems are installed at a depth in the ground to create the appropriate difference in surface and ground temperature.

It would be interesting to find a survey of the actual temperatures in various natural cellars throughout Europe to see what temps wine makers use/used in practice before air conditioning was introduced. I haven't seen such a census -- have you?

Bob, I wrote about the average temparature of regions, which, because of the fundamental application of the laws of thermodynamics, is exactly the average underground cellar temparature; the deeper you get, the smaller the annual fluctuations. 10°C is common wisdom in Champagne as in Germany. Burgenland is more like 11°C (although there's only a very small number of underground cellars, as in Bordeaux).

Michael, surely for me in Belgium digging deeper would solve my problem as I suspect that the average temperature here is around 12°C?

Exactly — provided you live in a place where you can dig deeper which is not always the case at low altitudes (high water table etc.)

Of course you can use air condition (cheaper) or drink your wines more rapidly ...

Another question is whether all wines mature optimally at the same temperature. 55F might be ideal for Cabernet Sauvignon, but 60F might be better for Syrah. Riesling might prefer 50F. I'm guessing that no one has looked into this. I've certainly never seen it addressed.

We are talking about chemical reactions here. Unless you have different chemicals in different wines (true, of course) which mature differently I don't see it making any difference.

It isn't impossible but I've never seen any evidence of this in the wine chemistry I've seen.

There wouldn't be any evidence if no one has done any studies.

A very good Bordeaux winemaker told me once (and I've said this here at least once and the comment was ignored) that if one has a wine fridge, in the winter one should lower the temperature about 1° C from where it is in the summer. I'm keeping it at 15°C and will soon go to 14°C for several months. This modifies the "stable as possible" theory to "change slowly like the seasons". IOW, make you fridge act like it's a real cellar.

Not a problem for me. My wine refrigerator is in the garage. It keeps the wine from getting too warm in the summer, but only mass and insulation keep the temperature up in the winter.

This is true, until you dig deep enough. Then, the temperature starts to rise due to the geothermal gradient, at a rate of 25-30C/km.