Air Lock

[two_one_seven]

What else can you do? What was going on the beer when said suck back occurred? Volume of star san in airlock, volume of beer, temp if it was cold crashing and so forth.

 

[hehawbrew]

I think uniondr post about temp change was my issue. New batch of beer just hour old. I usually use a blow off tube for the first few days of fermentation , but my brew buddy dosnt, and he put it together .

However, it's bubbling nice now!

 

[unionrdr]

Yes,temp changes can create a partial vacuum in the head space. Like when initial fermentation is done,& the temp drops say 3-6 degrees. I've had it happen.