Hey guys, so i have tried to find a answer but cant so i will turn to the pros. my blueberry mead is 4 months old and in the secondary fermenter carboy. everything was going fine until today when i went to check on it, the bung and airlock appear to be sucking in. ill try and post a pic. whats going on. the only thing i can think of is a temperature change but it has been in the basement and is a constant temp. the mead itself has no foreign growth on it that would indicate to me an infection. ideas???