So I put my imperial stout (expected ABV 9%) in the fermenter on Wednesday (now Saturday). Pitched safale s-04 onto 10.5 litres of wort at around 22 degrees C. So far there doesn’t seem to be much activity. The lid felt pressured but no activity in airlock. It’s sitting at around 20 degrees C. Should I pitch another packet of yeast? Any advice welcome. Thanks.

  • What type of fermenter do you use? Plastic bucket or glass jug/carboy?
    – Philippe
    Nov 4 '17 at 15:40
  • 1
    "Lid felt pressured but no activity in airlock". That shouldn't happen. Clogged airlock? Nov 4 '17 at 15:59
  • Is there a cap on the top of airlock that should be loosened? Has the inlet at the bottom become clogged? It is permissible to have a peek at the wort and see if it is fermenting and/or has a krausen. Have you tried taking a hydrometer reading? Nov 11 '17 at 9:15

Airlock activity is not a reliable way to gauge fermentation. Unless you have a perfect seal, you may not see activity during active fermentation. The only reliable measure of fermentation is a gravity reading. The only reliable way to tell if fermentation is complete (or has stalled) is to take gravity readings three days in a row and see if the gravity does not change. If it changes, fermentation is still in process.

Here's an article regarding airlock activity.


Is your fermenter a bucket with a lid? Second, you pitched at 22° C, most of your fermentation could already be finished. Take a look in your fermenter to see if there are small islands afloat, and traces of debris sticking at the side of the fermenter above the wort. Also, how does it smell?

  • Yes, bucket with a lid. Difficult to tell but given the amount of sugars in the wort I thought it would be bubbling like crazy
    – Carl Y
    Nov 5 '17 at 11:34
  • The other questions I posed are to check other signs that your fermentation already might be over, especially since you pitched at 22° C.
    – chthon
    Nov 5 '17 at 16:51

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