How do I know if fermentation is done?

[CoopBrew]

This batch has been fermenting for about 8 days now and seems to have stopped showing signs of fermentation. For example, the water in the airlock only seems to bubble once ever minute and a half. All of the (head?) has gone away. There doesn't appear to be any movement within the beer.

I know people say that typically your beer should ferment for 2 weeks minimum. But is it possible I screwed up (this is my first batch, and I had a minor issue with the liquid yeast). Should I just wait until 14 days has passed?

Thank you!

 

[CUrchin]

The only way to be certain fermentation is done is to get consistent gravity readings several (say 3) days apart. Your reading should be close to the intended reading to make sure you don't have a stuck fermentation.

As far as waiting, you will likely get some improvement in flavor and clarity by leaving your beer in the primary a longer period of time. For "normal" gravity beer, I usually go 3 to 4 weeks in the primary. Good luck.

 

[flars]

Fermentation is complete when Final Gravity is reached. Two or three Specific Gravity readings which are the same over a period to two to three days means FG has been reached.
A few more days for the yeast to clean up the off flavors of fermentation and sediment to drop out; you could bottle. And you could also wait a week if that would fit your schedule better. A little extra time is good for the beer.

 

[tallmike]

Shorter answer: Yes it's basically done fermenting, but wait the full 14 days at least. Weeks longer wouldn't hurt.

Longer answer: Co2 is a byproduct of the fermentation process, so if the airlock or blow-off tube is sealed and working properly, the rate of bubbling is directly proportional to the rate of sugar-to-alcohol conversion taking place in the fermenter. That said, it is a natural process over time that takes the form of a longnormal distribution, with a peak of fermentation (and bubbling rate) a few days after pitching, and an elongated tail that goes out weeks with slower and slower bubbling the entire time. The farther ends of the fermentation curve feature a conversion of the more-complex and harder-to-ferment sugars available to the yeast colony, and thus continue to contribute a change in character and taste. While not causing large increases in %ABV, the longer fermentation periods create a smoother and more nuanced homebrew. A better beer.

 

[MrHadack]

Coopbrew:

Since this is your first batch, I just want to ask to be sure: do you know how to take a gravity reading? Do you have a hydrometer? Other people above mentioned checking final gravity, but I want to make sure you understand what that means otherwise their advice might not make much sense.

 

[GHBWNY]

Ditto all the above. I'm a beginner, and brewing beer for the first time is like being thrown into a science lab with a bunch of foreign equipment and ingredients and running a never-before-tried experiment. And expecting a PERFECT outcome!

The "When is my wort done fermenting?" question was a big one for me, too. I was concerned about my airlock and its function in relation to when the fermentation was done. I have the cup-style with the floating check valve. It bubbled nicely for the first few days then stopped. But what I also noticed was that even though it quit bubbling, the inside of airlock had condensation fgor the next couple of days. Unless I'm wrong, the appearance of condensation would be an indication that there is something happening inside the bucket that is producing a temp higher than the room temp. The vets here told me what they told you: that the appearance of the airlock is not an indication of whether or not the fermentation is done. While it's fun to see your wort work for the first time VIA the airlock, the airlock is not a "fermentation gauge", it's simply an airlock. It cannot be used to determine what stage the fermentation is at.

SG, my friend. SG.

 

[CoopBrew]

Coopbrew:

Since this is your first batch, I just want to ask to be sure: do you know how to take a gravity reading? Do you have a hydrometer? Other people above mentioned checking final gravity, but I want to make sure you understand what that means otherwise their advice might not make much sense.

Yes I do! I recently took a specific gravity reading. But I'm gonna wait another week and test it 2-3 times after that. Thank you though.

 

[CoopBrew]

Ditto all the above. I'm a beginner, and brewing beer for the first time is like being thrown into a science lab with a bunch of foreign equipment and ingredients and running a never-before-tried experiment. And expecting a PERFECT outcome!

The "When is my wort done fermenting?" question was a big one for me, too. I was concerned about my airlock and its function in relation to when the fermentation was done. I have the cup-style with the floating check valve. It bubbled nicely for the first few days then stopped. But what I also noticed was that even though it quit bubbling, the inside of airlock had condensation fgor the next couple of days. Unless I'm wrong, the appearance of condensation would be an indication that there is something happening inside the bucket that is producing a temp higher than the room temp. The vets here told me what they told you: that the appearance of the airlock is not an indication of whether or not the fermentation is done. While it's fun to see your wort work for the first time VIA the airlock, the airlock is not a "fermentation gauge", it's simply an airlock. It cannot be used to determine what stage the fermentation is at.

SG, my friend. SG.

Thanks for the insight Pete. Always nice to hear from a fellow beginner. It definitely makes sense looking at the airlock, as simply...an airlock. I'll keep waiting and hope for the best. It's hard to be patient on the first batch...I'm so damn curious. Cheers.