How do you know when your beer is done fermenting?

[JSappenf]

How do you know when your beer is done fermenting? Is it when it clears? Is it when it is done bubbling? Is it when it reaches a certain specific gravity? How do you know that fermentation hasn't just stalled?

 

[rocketsan]

Hydrometer....

 

[irishrover32]

Take 3 gravity readings over as many days, if the reading is the same over the three days it's done, simples!

 

[Yooper]

It's "all of the above", sort of.

Sure, stable hydrometer readings are part of it. But to verify that it's done (and not stuck or slow), there are some other signs as well. One is that the beer will start to clear and visible activity will slow or stop.

When checking the hydrometer readings, not only should they be stable, but they should be at a reasonably expected FG. What I mean is that if the hydrometer reads 1.042 for three days, for most beers that wouldn't be finished- that would be stuck.

But if it reads 1.018 for more than three days (even if slightly higher than expected), it's starting to clear, the krausen has dropped, and it looks like beer, then it's done.

A reading that is higher than is expected should be investigated to make sure it's done.

 

[masskrug]

I have never kept an eye on my beers. I let them sit in primary for 3 weeks. When I go to bottle I use a hydrometer. If it is below 1.020 I bottle. If not, I'll raise the temp and rouse the yeast for another week.

 

[unionrdr]

Yeah,sometimes temp swings for instance can cause it to stall out. Gently swirl the fermenter to stir up some yeast & warm the fermenter up a little. It can take a day to get going again if it does at all. I try to get it as close to expected FG as possible in this instance.

 

[JSappenf]

Yeah,sometimes temp swings for instance can cause it ti stall out. Gently swirl the ermenter to stir up some yeast & warm the fermenter up a little. It can take a day to get going again if it does at all. I try to get it as close to expected FG as possible in this instance.

Well so I was brewing two batches at once and I mixed up my extracts. So my original specific gravities are off.

 

[unionrdr]

It'd be off a little,but 1.020 is still alittle high for an average gravity brew.

 

[JSappenf]

It'd be off a little,but 1.020 is still alittle high for an average gravity brew.

So my 5 gallon Lambic started off at 1.034 and my 3 gallon Belgian started off at 1.100.

 

[unionrdr]

That's possible,if you,for instance,used the same amount of fermentables in both. relative to the OG's anyway.

 

[JSappenf]

Yes, but using the recipe I had for the Belgian, its OG was supposed to be 1.067 and the final ABV of my Lambic was supposed to be about 6%.

 

[JSappenf]

So I checked the specific gravity of my beer. Its 1.01 and the OG was 1.1. Its still a little cloudy, but its been 4 weeks. Is it time to bottle?