I have a 19 liter carboy, and put a 18 liter wort. 10 hours later I woke up and noticed carboy overflow krausen all over it.

I am concerned whether air lock will clogged down and explode. I will not have a hose for another 6-7 hours, so blow-off tube is not an answer. I cleaned the air lock a few times, and it keeps overflowing, I see krausen in the airlock.

I am wondering what could be a solution? I am either thinking removing air lock completely for next 10 hours, or siphoning some of the wort to give some head space.

4 Answers 4


Few tricks for temporary fix.

Swirling every so often can get kausen to drop back in.

Nitrile glove with a pin hole in a finger will work for a DYI air relief cover, should limit the mess. Latex will work too but not recommended due to their odor.

  • 1
    Haha.. Maybe a balloon could work as well?
    – Martin
    Apr 10, 2018 at 14:14
  • @Martin yep, large ballons work. Kinda wrong, but unlubricated prophyalatics fit a carboy neck really well. Apr 10, 2018 at 15:18

You could do either of your suggestions, or if your carboy fits in a bucket, just let it overflow through the airlock until the blowoff tube arrives.


Have you considered using FermCap? It will reduce the Krausen without hurting the beer.

  • 2
    I've used it. It does reduce krausen head in fermentation but isn't a cure. It does work amazingly well in the boil. Apr 10, 2018 at 22:33

You could remove the cap and tape a piece of foil or plastic wrap partially over the opening. I’ve done this with Saisons to prevent back pressure stalling fermentation.

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