fermentation cycle

[jderm]

So my IPA is a little under two weeks old. The airlock was bubbling continuously the two days after the yeast was pitched, then it more or less stopped. I looked at it today and its bubbling one every 10-15 seconds. Why did it stop then start again? is this alright?


-jderm

 

[marubozo]

Chances are it isn't fermenting still and it's just CO2 slowly coming out of solution. It is still possible that the fermentation got a little stuck, slowed down for a while, and then something kicked it off again, but usually a beer with healthy yeast will finish fermentation in just a few days. But once the yeast eat up all of the available sugar, they are done.

The only way you can know for sure is to take a gravity reading.

I hesitate to even bring this up due to how unlikely it is, but there's also the very remote possibility that a wild yeast or some other contaminant got into your beer and started up.

Anyway, take a gravity reading and see if you're where you should be. Chances are you're just fine and the beer is just letting off a little CO2. Seeing bubbles long after fermentation is complete is fairly common and can be caused by anything from atmospheric pressure changes due to the weather or even a change in temp by a degree or two.

 

[Got Trub?]

Is it getting any warmer? Beer (any liquid) holds less CO2 in solution at warmer temperatures. If the beer is warming, even if only a few degrees, this will result in CO2 coming out of solution and venting out your airlock. Also if you physically disturb the beer by moving it CO2 will again come out of solution and venting through your airlock. Like marubozo said the only way to know for sure is gravity readings. Ignore the airlock.

GT