Air lock losing water

[CADETS3]

I have an Irish Stout on its 2nd week in a 5gal Whisky barrel and I found yesterday that the air lock was low on water and the plastic floater was sucked to the inside tube. I filled the air lock back up with water and reset the floater. 6 hours later it had sucked the water out of the air lock again. WTF..... I'm confused as to what is happening. Any help will be appreciated.

 

[CADETS3]

Temperature difference? From the beer to the house temperature?

 

[dkennedy]

I've never barrel-aged, but wouldn't the barrel absorb some of your beer as well?

 

[unionrdr]

Well, in my experiences, when I get a suck-back, a partial vacuum is created by the initial ferment temps going down. Lifting the airlock center piece will relieve the pressure. Put it back in & make sure it's filled to the line on the side.

 

[solbes]

Agree on temps dropping (most likely) or the barrel is absorbing your beer, creating a slight vacuum.

 

[HollisBT]

Probably just evaporation. The three piece airlocks lose water MUCH more quickly than the one piece S type air locks.

 

[brewer_in_the_cap]

I've been having this problem too (in a carboy though) but switching to an S-type airlock seems to have fixed it.

 

[solbes]

Probably just evaporation. The three piece airlocks lose water MUCH more quickly than the one piece S type air locks.

Agree on your second sentence completely, but 3 piece airlocks do not evaporate to empty in 6 hours. Even in the desert.