I can update this later with my specific notes/ingredients, but for now, just the basics...5 gallon brew of an irish stout. The morning after I put it in the fermenting bucket, I woke up to a mess. Foam had come out through the airlock and there was liquid and foam all over the lid and down the side. The amount of pressure building inside made it seem like the lock would blow off at any second (in fact when I removed it to clean, foam shot out through the hole.) I quickly found some instructions for a blow off type rig which was basically leaving the base of the airlock in the lid, attaching a tube to it, and running the tube into a gallon jug of half water/half sanitizer. The remainder of that day, it was bubbling furiously. It looked like rapidly boiling water. Since then however, I haven't really noticed any bubbling. There is pressure in the bucket still, because if I lightly push on the lid, gas will bubble through into the jug. Do I have anything to worry about here? The bucket is in a dark 65-70 degree closet. Any advice would be great. Thanks.

1 Answer 1


Absolutely nothing to worry about. A few notes:

  1. Active fermentation can certainly die down after 2-3 days.
  2. Airlock bubbles can indicate active fermentation. A lack of airlock bubbles does not necessarily indicate a lack of active fermentation. CO2 is sneaky - it can get out a lot of places besides through your airlock liquid.
  3. 70F is getting on the warm side for most yeast strains. Fermentation will produce heat of its own, meaning your beer could be several degrees warmer. It won't ruin your beer, but could produce undesirable flavors from the yeast.

So relax and let it roll for a week or so before you take a hydrometer reading to see how far fermentation has actually progressed. Checking the gravity is the only reliable way to know how fermentation is progressing.

  • 2
    Good answer, but I'd like to add a caveat to "Airlock bubbles do indicate active fermentation." The airlock can continue to bubble after fermentation has finished due to off-gassing. The active fermentation filled the beer with CO2, and the CO2 will continue to come out of solution for quite some time after fermentation has finished. So airlock activity tells you that fermentation is taking place or has already taken place. It isn't necessarily still active.
    – JackSmith
    Commented Jan 18, 2012 at 21:31
  • A good point, thanks @Jack. I guess I was over-simplifying.
    – JoeFish
    Commented Jan 18, 2012 at 21:50
  • 1
    Indeed. As a beer warms, the amount of C02 that can stay in suspension in the liquid decreases, thus producing bubbles in the airlock. A lot of people rack to secondary and see bubbles from the off-gassing and assume fermentation has started again.
    – GHP
    Commented Jan 19, 2012 at 14:13
  • 1
    Relax and have a homebrew. Great response Joe
    – gnome
    Commented Jan 19, 2012 at 19:11

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