Fermentation Troubles

[SoCalBrewer]

I just started doing mine fermentations in a temp controlled fridge. A problem I am running into is that when using a 3 piece air lock I seem to be pulling a negative pressure in the carboy which is sucking the water from the airlock into the carboy. I have my temp control probe affixed to the carboy and covered from the ambient air. So is there away to stop this from happening? Right now I have a blow off tube to see if this will stop the problem but would like some help with the air lock problem. Thanks in advance

[Mylo]

If you expect a crazy fermentation, then swap out the airlock for a blowtube into a growler of sanitizer. Make sure that you put the hose only about an inch below the level of the liquid. That way if it does continue to suck, once the tube fills with water - the vacuum will break before the liquid makes it into your beer.

If you don't expect crazy fermentation, then just put a sanitized piece of foil over the top until the beer temp stabilizes at your set temp. Once fermentation starts, you shouldn't have any negative pressure issues.


Mylo

[DannyW]

A problem I am running into is that when using a 3 piece air lock I seem to be pulling a negative pressure in the carboy which is sucking the water from the airlock into the carboy.

Just don't fill the airlock so full. The liquid only needs to cover the vent holes in the internal piece, not be all the way up to the fill line.

[Lars]

Sounds like you are putting your fermenter in the fridge with the wort still warm and then reducing the temp further. The expansion/contraction of the wort is causing the negative pressure. One solution is not to airlock your beer until it is at ferm temp, or use a blow off tube like mylo suggested.

[SunkenBier]

I think Lars is on the right path. I put on the three piece airlock without the water. This stops anything from falling into the beer. Once the fermentor has reached the desired temp I want I add my vodka to the airlock.