Let me help you out a little, Gerhard, it is not a personal problem, it is personal taste. As in subjective. And yes, I don’t think I am the only one here who has an antipathy towards high alcohol wines. And yes, you may feel subjectively a huge alcoholic monster weighing in at 16% may be in balance, I will likely find it hot and nasty. That is one of the nice thing about wine; we are not all chasing the same bottles.
Can alcohol evaporate from wine like it does from spirits? (Angel’s share)
Not sure if you asking about evaporation during barrel ageing or in bottle. In either case the answer is yes. Both alcohol and water can evaporate and diffuse over time, and which one evaporates more rapidly is dependent on the relative humidity of the environment. Higher humidity environments favour more alcohol loss, while lower humidity environments have the opposite effect. It’s part of why temperature and humidity are such important variables in the production and ageing wine and spirits.
I mean in bottle
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The method of evaporation doesn’t change whether the wine is kept in a bottle, a tank, a barrel or any other vessel. Only the rate of evaporation.
If a wine is bottled, I’d assume everyone wants the rate of evaporation to be as close to zero as possible. At least I buy wines to drink myself, not get angels drunk.
The “angel’s share” is from barrel, not bottle.
Yes I know, but I was curious if there’s any data on whether there is significant reduction in abv over time through evaporation. I guess the only way to know for sure would be to analyze a wine immediately on release then 10 years later, or whatever. Of course I suppose the rate of evaporation should be low if the wines are kept at cellar temperature but I assume it’s still not zero. I have some containers of water in my cellar for passive humidification and they certainly evaporate very slowly but they do evaporate. Clearly the surface area in a bottle is less, but ethanol has a significantly lower boiling point.
Just as Rodrigo said, the reduction (or increase) in ABV depends on the air humidity. In ideal conditons, ie. high humidity, alcohol evaporation might happen at a slightly higher pace, but you’d have to lose quite a bit of volume to see any noticeable effect - and at that point there is enough headspace in the bottle that most likely the wine is pretty much ruined.
The difference in boiling points does not really matter at cellar temps. Boiling and evaporation are two main methods of vaporization and we’re discussing about evaporation here, not boiling. Evaporation happens as long as the air is not saturated with the molecules that can evaporate.
I guess the main question is whether we think alcohol vapor can cross the cork. My general guess is that evaporation to a degree that will decrease the ABV of wine probably doesn’t happen to a significant degree, given that old wines still have significant abv, but just a thought.
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I will add that at the same relative humidity, higher alcohol concentrations (ABV) will see a faster rate of evaporation overall for both alcohol and water.
It’s much more conductive to check out relevant research instead of trying to guess whether something happens or not:
Cork is permeable to ethanol vapor, although noticeably less than to water vapor.
However, both liquid ethanol and liquid water decrease the permeability drastically - which is the main reason the cork should be kept in contact with the wine.
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That study examined uncompressed cork. Also, there is dramatic variation in the closure types, especially comparing older bottles, where there may actually be a significant change. Also, one would also assume that evaporation would be higher with higher abv wine. There’s lots of variables to consider.
I seem to remember Penfolds doing a study in the nineties and finding huge differentials between corks and the tightness of the closure on the same bottling line.