So I've just finished my 3rd all grain brew yesterday, first time trying a stout.

After 24 hours, I'm only getting ~4 bubbles per minute on the airlock.

Last night about 8 hours after pitching the yeast there was practically no activity so I'm thinking the yeast could just be slow..

I'm worried about that the yeast activity won't pick up sufficiently if it hasn't already.

Also there is there is a little bit more empty space in my fermenter than I've had in previous brews, could this be a factor?

Temperature is pretty constant at ~21c

5 Answers 5


Airlock activity is not the be-all end-all. You could have a bad seal on a bucket or on the airlock grommet itself. Give it a little time (3-4 days) then check the gravity. Gravity movement is really the only 100% reliable way to test if the yeast is working.


Fermentation needs lots of oxygen.

What I usually do in my 10 l batch is to shake my fermentation vat to add more oxygen to the wort before pitching the yeat and put the air lock on the vat.

I assume you started your yeast before pitching it.

I once did not do that and sprinkled the dry yeats over the wort as per instructions on the package, however, it took some time (a day) for the ploptivity - :) - to present itself.

  • Do NOT shake your fermenter if the yeast has already starting working. Doing so could oxygenate new beer and you do NOT want that. Wietze is right that you certainly can shake that vat just before/just after you pitch. But once the yeast starts, leave it alone. :)
    – Ell
    Apr 26, 2016 at 19:22

Sounds like everything is doing fine.

8 hours of lag time isn't bad at all.

Extra headspace has no effect on actual fermentation and little effect on air lock activity, though c02 does slightly fit in between molecules in air as it mixes, it's so small it's only a matter of note for novelty.


As the previous posters mention it sounds OK just a bit of a slow start.

If after 48 hours you are still concerned, take a gravity reading and if it has not noticeably dropped, then re-pitch a new starter.


I wouldn't be too concerned by it but just be sure to keep up with the gravity reading to check for real progress. That's the surefire way to make sure your beer is doing what it's supposed to. Airlock activity isn't the only sign.

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