About 2 years ago, I added a digital thermometer to my passive cellar. Its a Twine that sends an email on temperature change, which gets slurped up by IFTT to a Google Spreadsheet. Convoluted, but it allows me to have raw data over time to play with as I please.
The warmer weather recently here in the bay area prompted me to take a quick look at the temperatures. Since inception: min 51F, max 70F, average 62F. It can see a 5F swing over the course of 2-3 days in the open air, though I suspect the wine only sees a fraction of that in their shipping boxes and with their thermal mass.
Not bad. I’m considering storing more of my wines in the passive cellar. My question for you: how much do you think this environment accelerates aging over a professional storage facility?
In an ideal world, you’d have lower peaks and fewer short-term swings, I guess, but I think you should be fine.
For 10 years, I stored wine in my uninsulated basement storeroom in an apartment building in San Francisco, which had similar temperature swings. The air in the room sometimes got to the low- or mid-70s in September, but I had 35-40 cases in wood and cardboard boxes stacked on a shipping pallet so I assumed the thermal mass worked in my favor, even though three uninsulated walls faced open-air areas.
While I don’t have control bottles for comparison, I never had any problems I would attribute to storage, and 20 years later I still have some wines from that period. An '86 Cos d’Estournel I opened last year that was stored there from release was still relatively unevolved – certainly not past it!
I have two comments.
You have a 19 degree peak to peak swing, and within any given month it looks like about a 7 degree swing. Wine is best stored in a constant environment, so when I look at the data, I have reason to be concerned.
Second comment, and this is a “take it for what’s it’s worth” comment. God forbid you were ever in a situation where you had to sell off your collection, some houses would reject the collection, and if someone was being forthright, they would say “removed from passive storage”, and the results would absolutely be lower than if it said “removed from professional/temperature controlled storage”.
If stressed about it, I know people who have set up a digital thermometer inside a wine bottle filled with water and sealed in with a suitable cork/bung. This touches on John’s comment about thermal mass, and especially the temperature inside the bottle takes quite a while to reach the temperature outside the bottle.
Personally I’d not get over-stressed by this, but if it is stressing you, then the exercise above will either give you peace of mind, or make up your mind to do something to address residual concerns.
I would just note that this common wisdom was challenged in some other threads. I think Greg Tatar was the main challenger. As I recall, the bottom line is that it might be true, but there’s no research to show that fluctuations are a problem so long as the temperatures don’t get too high.
A 5 degree change over three days? How often is that? For me it’s a large temp differential let alone the time it takes. Then the overall temp differential of 19 degrees over each six month time frame. Too much for me to accept. 70 degrees is also out of my allowable temps.
For a long time I stored my wines in my friend’s passive basement. Temps fluctuated between 48-55 through the year with peak months of change being June-August often increasing by two degrees each month. All the wines I’ve opened from that cellar have been exactly what I look for. Slow to mature, and nothing giving me any cause for concern. They were in this basement for 3+ years. Nothing shows any sign of premature aging…and I’m not concerned at all.
However, while in Italy I bought some wines that had been released in the last two to three years…and they all show signs and of heat exposure from the passive basement there. My guess is that not all assume basements are the same and depending on how big or how quick the temps fluctuate also depends on the impact.
Although the temp. in MY passive cellar is lower generally, and less variable …
e.g. in Chateauneuf-du-Pape I´ve met cellars that are even warmer in summer … and the wines were ok …
so keep cool …!
My estimate is: maybe 5-10 % difference to a professional cellar (that means 90-95 instead of 100 years ageability …)
"The temperature of a cellar is an essential factor where variations are welcome as long as they are measured and progressive. The cold of the winter doesn’t really bother the bottles if the temperature is above 10°C (50°F) nor does the heat of the summer if the temperature doesn’t exceed 18°C (64°F) for too long. An average temperature of 14°C ( 57°F) is ideal. "
Rama, I’m in the camp that doesn’t worry at all about temperature swings, either long term or short term. I just don’t believe that makes any difference. Really, the only thing to have any concern about is the length of time at the higher temperature range, say 65 and higher. Even that won’t hurt your wine (IMO), but it will move it forward slightly on the aging curve relative to a constant 55.
Where is the cellar? If it’s on contact with the ground, or a crawl space, I’ll bet you would see a difference in temperature between ground level and higher up. If so, you could consider storing your most ageworthy wines at the bottom of your stacks, and put things you’re likely to drink sooner higher up.
One note that drives buyers crazy is SSOS (slight signs of seepage). A lot won’t bid, and their reason is they think something went wrong, most likely not stored correctly. That doesn’t happen when the wine comes out of a correct cellar, and I see it a lot in passive cellars.
I’m not worried about the temperature swings seen here. As I mentioned, I think the data is misleading since its measuring ambient air temperature. Alan, the space is my garage, which is under the house. So its like a hybrid between being on the ground floor and the crawl space. Ian, I’ve stored wines here for 13+ years and have never had seepage or otherwise heat damaged wines- nor would I expect it at these modest temperatures.
Is there a generally accepted belief on this, like “for every increment of +/-5F above/below 55F, expect aging to accelerate/decelerate +/-5%”? So if the wine spent (let’s say) the months of June/July/August at 65F and all other months average out to 55F, you’d be looking at 10% * (1/4 of the year) = 2.5% increase in aging rate. (I know, this is highly simplified- just looking for a wag here.) At my average temperatures, that seems roughly in line with Gerhard’s beliefs.
I have an active cellar now for the past 15 years. In summer its actively cooled to keep temp at 15 C. Winter I turn off cooling and temp can swing from 11 to 15 C. Never had an issue with the winter temp swing.
In Sydney I had a passive cellar with swings and higher higher temp. Similar to yours. My wines looked OK tasted in the short to medium term. At that time I was collecting mostly robust Australian shiraz and cabs etc. Perhaps they are slightly indifferent to temp swings and can tolerate slightly higher temp. I finished or sold off most of wine from that cellar as I moved to mostly collecting Burgundies, Bordeaux and Italian wines since moving to Melbourne. So I do not have lots of long term data points on the passive stored wines but I do still have some wines from that era i.e. 1994 - 2000 vintage which are still drinking very well. In the short term (< 10 years) they looked fine.
Certain wine styles are perhaps more demanding. White burgundies and Champagne perhaps. I have seen more bretty CNDP ( and few Bordeaux too) coming from warm cellars.
Some wine stored in warmish cellars taste OK in isolation but appear to taste “less fresh or vibrant” when compared to cool stored wines. This aspect was noted at our offlines when two identical wines from passive and active cellars were tasted together on a number of occasions (accidentally).
I’ve seen that in a cellar I shared where temperatures got in the high 70s for several months. Sweet wines seeped big time. (Happily not my bottle!) I never had seepage problem in my San Francisco cellar, where the ambient temperature did creep up into the 70s in the fall. That was almost all dry reds, though.
It’s very cheap and easy to add a box air-conditioned to most passive cellars and turn it on over Summer/early Fall. Stops the wine going into the mid 60s. I did it and I think it’ll make me live a bit longer as well as my wine
People schvitz over the minutiae of terroir until it gets into the bottle, and then it becomes some industrial controlled microclimate? Let the wine live in life. Temperatures fluctuate, climate varies. People need to separate themselves from electricity; aside from the prices, Baron has it correct in this respect.
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