Pure ethanol, or as close to pure as you can get since it is hydroscopic, evaps fast at room temp.
But what about in a mixed drink, or beer or wine? I’ve seen people drink wine left out overnight, or a opened beer, is there any alcohol left at this point?
The hydroscopic does not to my knowledge aid in the evaporation, but that water held in humidity in the air will come out into the ethanol and dilute it. This will balance at about 180-190 proof.
I friend of a friend (who makes a good living) likes to occasionally drink shots of Johnnie Walker Blue Labelat our local tavern/restaurant (at $23 a shot*!*). Recently the bar installed plastic pourer spouts on all the liquor bottles. Upshot of this is that the bottles are now no longer capped shut, but open to the air 24/7. My friend’s friend claims that since they did this the Blue Label doesn’t taste right because a large amount of the alcohol & flavor has evaporated out the open top.
Given how expensive it is I’m not prone to think he’s making it up, but I don’t drink scotch. Does this sound plausible?
According to this grad student experiment preferential evaporation of ethanol is strongest around 50% and negligible below 10%. And this ran over a week, but the methods are highly susceptible to errors, so my “Yes, there’s alcohol left.” is in my opinion only 80% likely to be correct.
Alcohol forms an binary azeotrope with water, and the weight fractions of water and alcohol in the vapor space above the beverage will vary with temperature. At, I think, around 141 deg F you’ll evaporate around 90% alcohol and only 10% water, but as the temperature decreases to ambient you’ll evaporate less alcohol and more water. It’s also complicated by the fact that this varies not only with temperature but with the weight percentage of alcohol in the liquid phase as well. It would take a very long time for all the alcohol to evaporate, much more than overnight.
And, as we’re in general questions and giving only true facts, for half the price and a much better taste Hail Ants friend should be ordering Lagavulin.
Plausible that it tastes different, because of oxidation and contamination with whatever is in the bar’s air. Especially if the bar allows smoking.
But a slight increase in the percentage of water doesn’t strike me as a likely culprit.
It’s more than plausible - it’s probable. One of the problems with the bottle spouts being left on throughout the life of the bottle is that the alcohol will interact with more than just water vapor. In those places (if there are any left) where smoking is still allowed, you’ll get a tobacco flavor (the cigars might be good, but that stale smoke is gross). Most bars also use some pretty strong cleaning products, and those will also insinuate themselves in the exposed booze. Scotch is fairly fragile, in terms of flavor. Some bars using bottle spouts will at least cover everything with plastic wrap at the end of the night. I get disgusted with the ones that just leave them exposed, not only because of the flavor implications, but also because I don’t particularly like drinking fruit flies.
Plus, as the water/ethanol shifts toward water, some flavor and scent compounds become less soluble and more likely to escape.
PS, hygroscopic
Based on an admittedly brief Google search for the devices, it looks like the ones with flip tops cost only $0.50 more than the ones without. It would be hard for me to patronize an establishment that thought so little of its clientele that it would allow them to drink fruit flies for a lousy couple of quarters.