Airlock pressure vanishing

[djlee84]

Hi, sorry if this seems like a stupid question but im worried about my baby. I have been brewing a extract kit (never had problems before) brewing a lager had it at 15-18degrees c and the brew has been happily bubbling away for over a week. my question is last night all the water was at one chamber in the airlock and bubbling away contently, this morning aprx 8 hours after all the water in the airlock is completely level and no signs of bubbling. i checked the lid but no problems, i understand if fermentation has finished but surely the remainding co2 should keep the water in the airlock pushed over. can anyone shed some light on this to keep me from worrying.

cheers

 

[Schnitzengiggle]

When the tamps drop after active fermentaion the pressure inside the fermenter falls, and can suck any liquid that is int he airlick back into the fermenter.

If you are using alcohol, or sanitizer then .... no probs, usong plain water, es no bueno

 

[djlee84]

Oh o, i have plain old water, it was boiled before adding, luckily its only sucked back to level, i dont see that i have lost any water. thanks a lot for the reply

 

[BobBailey]

You're just seeing the effects of temperature and pressure changes that normally occur when active fermentation ends. Temperature drops as activity decreases and more CO2 will stay in solution at the lower temp. When CO2 production stops and temperature stabilizes the water may just sit in any position or may move a bit in either direction.

One good thing about using an "s" type airlock. Unless it's overfilled it won't allow liquid to be sucked into the fermenter. I don't like them for active fermentation, but they're great after that, allowing you to cold crash without worrying about sucking up the liquid.

Bob