Alcohol evaporation after fermentation

[jarenault]

Is this a recognised phenomenon?

I brewed a big IPA recently. Went from 1.068 to 1.012 and it tasted like it! At least when I tasted it during my gravity checks. I left it for a couple of weeks after I was sure fermentation had stopped, just to settle out. Now it's bottling day and the alcohol taste has all but gone.
It wasn't a harsh alcohol taste earlier... just tasted like a nice, strong beer. That's gone now.

I just wondered if alcohol is known to evaporate off significantly after fermentation is done. Of course the alcohol is more volatile than the water so % ABV will necessarily reduce over time in an open system, but does anyone know how significant this reduction is?

 

[bobsbeer]

Very unlikely unless you have stored it in a very warm place. More likely the change is due to the conditioning.

 

[jonewer]

Alcohol does evaporate faster than water - which also evaporates.

Its a problem for whiskey distillers where the product is in wooden casks for a decade or more. This means the strength of the product deceases and there is an overall loss - which can be considerable for very old malts. But a few weeks in a plastic fv is not going to be an issue at all.

 

[RobWalker]

i think you are experiencing maturation.

hot alcohol taste comes with a young beer. it wears off after time and it'll blend into a great tasting beer. i find anything under 7% doesnt taste of alcohol at all given a little time.

for a more obvious example, try drinking some young wine, it's like battery acid for a few weeks.

 

[evanvine]

Its a problem for whiskey distillers

You wouldn't deny the Angels their share, would you?

 

[jonewer]

Its a problem for whiskey distillers

You wouldn't deny the Angels their share, would you?

Is there a minimum alcohol price in heaven?

 

[pittsy]

no (its heaven) but there is a minimum 2 drinks entry .

 

[Moley]

Its a problem for whiskey distillers

You wouldn't deny the Angels their share, would you?

Is there a minimum alcohol price in heaven?

No, they get theirs for free, wooden casks need to breathe and it's all part of the process.

I was going to post the comment but Jim beat me to it.

That's what the loss from casks during the maturation period is known as, "the angels' share".

If you ever get chance to visit a malt whisky distillery, the aroma in the bonded warehouse is quite something, I'm sure if you stayed in there for an hour or so you could get pissed just by inhalation.