Airlocks that suck

[jamis]

Has anybody had there airlock suck all the water back into the fermenter?
I have just encountered this problem with my air lock this morning, this time I used the bottle half filled with sanitised water method as it was a particularly vigorous fermentation, I changed the water in there about 3 times, except the last change of water I dont think I used sanitised solution as the bubbles and fermentation had finished .  This morning nearly all the water was gone, about a cup, the water in there was about 4 days old, so I,m thinking its probably going to be infected.
The fermenter was about 22 when I turned the heat pad off ( I have aluminium venting between the fermenter and the heat pad so its not in direct contact)  overnight was cold and in the morning the fermenter was down to about 10, I,m just wondering if some sort of  thermal contraction happened here, this is about my 8th  brew and  hasnt happened before, is this a winter phenomenon?

[Patrick]

Can't say I have experienced this, but if the air temperature in the head-space dropped by 12 degrees then it would definitely contract enought to suck a fair amount of water in. Now you have me worried about the water level in my airlock!!

[MrC]

I've heard of it happening. When the temp goes down the liquid shrinks and the airlock gets sucked. It should only be an issue with blow-off tubes, the standard 'S' shaped airlock will simply bubble inwards for a while.

[Toot]

I fill my airlocks with vodka or some other strong spirit for this reason.

[MrC]

I fill my airlocks with vodka too.

[Nolen Smith]

Yep, vodka is the way to go.

[Doublehoppy]

I use starsan solution at the normal dilution rate. As a small amount of starsan is apparently OK in the wort/beer I wouldn't have thought this would be a problem. Or am I wrong?

[Simon David kelly]

I've had it suck back when the heater pad crapped out and the temp dropped to 5 from 20C. Fortunately I was using vodka and the smallest amount of it was left in to just keep the seal.

I've also sprayed the walls with it by having the temp too high and had a very very rigerous ferment.

As long as you check it regularly and use distilled water or very high alcohol spirit you should be fine.

[warra48]

Forget the lid and the airlock!

Use clingwrap instead, and use the rubber seal from the inside of the lid to hold it in place.

Who needs the bloop blip bloop blip from an airlock?

[jamis]

I was using a blow of tube into half a bottle of water at the time, in future I will only use this method for particularly vigorous ferments and once everythig slows down will switch to S airlock

[JoKing]

I don't even use Airlocks.

[studio1]

what do you use? tinfoil?

I've got some of these on the way http://morebeer.com/view_product/16797//Sanitary_Filter which may come in useful.

[JoKing]

Yeah - I figured if is good for starters, it's good for my beer!