Yeast Fermentation and 'Clean up' periods?

[Psylocide]

I'm kind of curious about something.

Let's say a batch ferments down within the first week to a stable FG (say a light beer, relatively low OG, etc.).

If someone were to post the question, "Is the beer done?" It would seem that almost invariably, people will start telling the brewer to "wait at least another week to let the yeast clean up after itself and remove any off flavors" etc.

My question is, other than clearing up "off" flavors, what else goes on during this period?

The reason for this question is because my last two brews have been done fermenting within a week at the very most (impatience led to early hydro samples), and the taste from both were great. Exactly what I had expected, if not better.

I feel that my palate is pretty well refined in all things beer/food, and have not noticed these "off flavors," save for my Irish Stout, which I was able to pick up in an instant. 2 more weeks fermenting and it was gone.

So again, what else is happening if off flavors are not present and SG is stable?

 

[wailingguitar]

When the beer is done, it's done. If it tastes the way you want it too, you're fine.

At our brewery I look for about 2 weeks, brew to glass, on my ales. We use SO4 and it finishes up in about 4-5 days typically. I then have it crashed for a week to start clearing and get carbonated. If I left it longer, it would drop totally brite in the FV, but we don't have time for that. It will get totally clear in the keg or can on it's own.

 

[hanuswalrus]

I don't know a whole lot about the science behind it, but I believe the yeast continues to clarify the beer as well as clean up off flavors during this phase

 

[sandyeggoxj]

There is some diacetyl that is produced. Warming the beer slightly helps the yeast clean up some of those compounds. Also, the beer is still "aging". There is a certain amount of time that it takes to make beer that can't be rushed. If you like it young then no worries. Carb and drink! I try to give my beer about 10 days in the fermenter. The last couple I will usually raise the temp to 70-71, depending on the strain. Then if I need to dryhop I also do that at around 70.

 

[skunkfunk]

Acetaldehyde and diacetyl are about the only "normal" reasons you might need to wait another week. If everything went well and you're sure it is at terminal gravity, I like to bump the temp up to check for diacetyl - 68F or so is usually sufficient. After that, cold crash and package, whatever you normally do.

Many times, I think people put stuff in their beer or had bad processes when they like to give a month+ for every beer. Too roasty? No, it's not that beer needs more time, it's that you used too much roast. Too hoppy? Again, don't hop so heavily. Green apple beer after 3 weeks? Hot alcohol flavor? You fermented too warm for the strain, underpitched, or made some other mistake.

Now, I've had yeast that took its damn time finishing (my first saison comes to mind, those can seemingly drop a point every several days for a maddening length of time) but I've also brewed a 12.5% RIS with a saison yeast that was done in 2.5 weeks and delicious, no aging required. Whatever.

My 2 cents.

 

[Psylocide]

Thanks for chiming in, this is somewhat what I expected, so that's a nice confidence boost.

Aging is a totally separate part of the equation as far as I'm concerned. I was really just curious about what is actually going on with the yeast at this point, and what that means for the beer. If no off flavors be present, and FG is stable, why not crash/fine (if desired) and package?

Appreciate the feedback.