Which is better to control cellar temperature—measuring air temperature or liquid temperature?
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Dear Dr. Vinny,
Which is better to control cellar temperature—measuring air temperature or liquid temperature?
—Brian, Castle Rock, Colo.
Dear Brian,
The temperature of the air inside a cellar or cooling unit and the temperature of the liquid inside the bottle are not necessarily the same thing. Some wine-cooling units are controlled by the ambient air temperature; others rely on the temperature inside the bottle with the use of a bottle probe, a device inserted into a wine bottle filled with water in your cellar.
Why does it matter? Quite simply, the air temperature can fluctuate quite a bit while the liquid temperature will vary much less. Not to get too science-y, but liquids have a thermal mass inertia that is insulated by the bottle. Air temperature changes much faster because air is lighter and more sensitive to changes.
The concern about bottle probes is that because liquid will change much more slowly, by the time the measured temperature gets warm enough to trigger cooling, it might be too late, or at least it will take much longer for the temps to get back to ideal. But at least you know what temperature is inside the bottle, as opposed to just the air around it. Most coolers that are regulated by air temperature allow for a handful of degrees of fluctuation around the target temperature.
I think both do the job. I see most units are air-measured, which is just fine. Years ago, I also fashioned a bottle probe inside an air-temperature cellar. I took a bottle of wine that I filled with water, put a cork in it and stuck a probe thermometer through that. There was nothing fascinating to observe—the temperature inside the bottle was stable.
There are also a couple of other gadgets to help you measure a wine’s temperature. For a few bucks, there are flexible, bracelet-like cuffs that wrap around a bottle and, assuming they're in contact with a bottle (trickier for some bottle shapes), will give you the temperature of the outside glass of the bottle, which should be reflective of what’s inside. For a few dollars more, you can get an infrared thermometer that you just point at a bottle of wine and get the temperature of what’s inside without any contact.
—Dr. Vinny
