How to Know When Fermentation Has Finished

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Portrait of Emmet Leahy

Emmet Leahy is the Chief Operating Officer and lead product developer at Clawhammer Supply, a small scale distillation and brewing equipment company. He loves the process of developing new equipment for making beer at home just as much as he does using it to brew his own beer. He's also passionate about teaching people how to use distillation equipment to produce distilled water, essential oils, and with the proper permits, fuel alcohol and distilled spirits.

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96 Comments

  • SA
    Comment Author: Stumpy Al

    How long can fermentation sit after bubbles stop?? Is 2 or 3 days ok ??

  • L
    Comment Author: LEwis

    After fermentation do I need to let the mash set a few days before running it?

  • J
    Comment Author: Joseph

    It states in this in this article pretty clearly that 1-2 minute spacing between bubbles in the airlock means it’s done, especially if it’s been fermenting for 14 days already. This is also not a place to ask questions, but to make comments.

  • V
    Comment Author: Vince

    Hi. I have a 5 gallon bucket of mash working, and I’m getting bubbles through air lock every 1.5 -2 minutes. How much time do I have before I have to run it before I’ve waited too long?

  • J
    Comment Author: John

    I am on my second run. My first run didn’t turn out so hot as we were brewing up that batch every drop came out cloudy or had a taste of water with no alcohol content at all. We think we jumped the gun but our yeast wasn’t fizzing or bubbling as you said in this post still came out as water. Now this next batch we are running would it have a natural smell as to when the yeast is done with fermentation?