So I brewed an IPA about 2 weeks ago. I used a glass carboy for fermentation and for the first 2 days it was heavy bubbles then for the next week and a half there were a few tiny bubbles. I checked today and the bubbles have increased greatly. Why is this?

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    By "bubbles" do you mean foam on the surface of the fermenting beer, or bubbles in the airlock? Jan 12, 2014 at 16:10

2 Answers 2


The most common reason for a fermentation fluctuation like the one your experiencing, I think, is most likely the temperature of the area around your carboy. Put one of the cheap strip thermometers on it and take readings a couple of times a day. I had an electric heat band on my carboys in the winter to try and keep the temperature at a constant. I suggest keeping a eye on your hydrometer readings as well. The only other thing I can think of, if it's not temperature, it may by a pre-warning to the fermentation sticking. This can be caused by old yeast, not using a yeast starter or any number of other reasons. If it does stick have some fresh yeast on hand and repitch. Hope someone else writes in too if they have also experienced something like this.Good Luck Kiwi Bruce


Yes Kiwi Bruce what you said just confirmed my fears that it was the temperature. I have my carboy in the warmest area of my house, but living in colorado its not easy keeping the house warm especially at night. So if the yeast go dormant an slow down is it possible to revive them with warmer temperature. The yeast I used is Wyeast American Ale.

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