Does the alcohol content of wine go down after three days of being opened if I refrigerate it?
Interesting. By placing it in the fridge, do you hope to better preserve the wine or are you trying to avoid losing a precious drop of alcohol? Just curious!
I digress. It's true that wine's alcoholic concentration can decrease when exposed to air. It's a simple matter of evaporation. Wine consists almost entirely of water and alcohol. Since alcohol is more volatile than water, it will, by definition, tend to evaporate faster. However, the relative evaporation rates depend on what's going on above the surface. In a moist climate, alcohol evaporates considerably more quickly than water. This is because the surrounding air, being sufficiently saturated with water, can't readily accept much more. By contrast, there's no alcohol in the air, so the alcohol in the wine sees a free and clear path to escape without overcrowding.
Consider the evaporation dichotomy between whisky in, say, Scotland and Kentucky. You may have heard of the "angels' share." That's the romantic term for the gradual evaporation of a maturing spirit through the pores of a wood barrel. It's a big inventory cost to most distillers, with common annual volume losses of 2 to 4 per cent. In Scotland, where the air tends to be cool and moist, much of that disappearance comes in the form of alcohol. That's why a newly distilled whisky that enters a barrel at 62- or 63-per-cent alcohol from the still can drop to the low 40s after 40 or 50 years. In contrast, in Kentucky, the air is much drier, so the water component of bourbon tends to evaporate more quickly than the water component of Scotch, keeping the alcoholic strength on a more even keel as bourbon matures.
So much for whisky. You asked about wine, where the alcoholic concentration is much lower to begin with. And we're talking three days, not years. That's nowhere near enough time to produce a significant change regardless of whether you store opened wine in the fridge or not. Rest assured, your hangover will be just as potent three days later as if you'd just pulled the cork.
The Flavour Principle by Lucy Waverman and Beppi Crosariol was recently named one of this season's Top 10 cookbooks in the United States by Publishers Weekly. Published by HarperCollins.