Filling it up just to the line... I have it in a temp controlled freezer. You think it might be a difference in temp between the freezer and the carboy?Thirsty1 said:Sounds like you are filling the airlock up to much- past the center cylinder. Try just filling it 1/3 but enough where the bottom of the "air cap" is submerged. Also try using cheap vodka instead of water. It will stay sterilized, keep insects from getting in during the summer, and if any does get sucked into your carboy... you see where that is going.
Doesn't matter how fast/slow you cool it. The air in the carboy is going to shrink the same amount, and suck the liquid frm the airlock.Evan! said:Cool it down slowly. For instance, if the freezer is set to 62f and you stick a carboy full of 80f wort into it, there's gonna be a big differential and you may get suckback. So, set the freezer higher, and slowly chill it down.