FTSs/airlock question

[pursuit0fhoppiness]

Hey all, I have a 7 gal SS BrewBucket with FTSs. How come when my FTSs kicks on, like half of my vodka/sanitizer in my 3 piece airlock bubbles and gets sucked into fermenter? I have to keep refilling it and it's quite annoying (and adding vodka to my beer).

 

[yowzers]

Air would be getting sucked into your fermenter if it was getting cooled rapidly and the headspace gas contracts. If a good portion of the cooling coil was above the liquid level, you could be chilling the headspace gas quickly and causing it to contract.

 

[mredge73]

Lots of people build double air locks with mason jars to keep this from happening.
Some people use balloons. I pressure ferment, but use a water filter housing to protect against suck back and blow off.

 

[pursuit0fhoppiness]

Yowzers, this was a 4 gal batch so that makes sense. Thanks! Should've used my coil extensions for this batch. Might try to add them when dry hopping in a few days.