Clean up

[hulkavitch]

I have read that after fementation is complete (fg same on consecutive days) the yeast go through a clean up phase and should be left to sit longer to avoid off flavors. Is this true? Does the beer need to be left in the fermenter at that time? Can this be done in bottles? Does any one know how long this is?

 

[slarkin712]

This is true. You should leave the beer in the primary fermentor for a few days. During the main active phase of fermentation yeast produce compounds that can later be consumed when the yeast run out of the fermentable sugars in the beer. Basically the yeast will continue to feed on anything that they can find. This is best done in the primary when there is the most yeast in contact with the beer. If you move the beer to a secondary or bottle there is less yeast in contact with the beer to "clean up". That said, clean up can occur in the bottles, it's just more effective if left in the fermentor. Can't give an exact time for this clean up phase to complete, but leaving the beer in the fermentor for up to a month is usually OK, and doesn't have any negative effects on the beer.

 

[Yooper]

Yes, the "clean up" is true. After fermentation slows, the yeast are still active and scouring around for more food. Once the fermentable sugars are gone, they will go back and eat less preferable foods- like their own waste products.

This process is over in 24-48 hours, generally, after the beer has reached it's FG (final gravity).

Then, the yeast will become dormant and fall to the bottom of the fermenter, leaving clearer beer behind. That's a simplification of course, as there will still be billions of yeast in suspension, but it's the jist of what happens.

 

[hulkavitch]

What if you are transfering to fruit puree in secondary. Do you wait for the yeast to cleanup where they are just going to start fermenting again when they get to the fruit?

 

[sweetcell]

What if you are transfering to fruit puree in secondary. Do you wait for the yeast to cleanup where they are just going to start fermenting again when they get to the fruit?

i would think that yes, let the primary run its full cycle - including clean-up - before moving to secondary. waste products aren't a favorite food for yeasts so you want them to consume whenever possible and as soon as possible. don't leave 'em sitting around.

patience is the strongest virtue when it comes to brewing. yes, you can push things through faster - but your beer won't be as great as it could be. i typically enjoy a batch for months so what's an extra 4-5 days to the process to ensure that i have the best beer possible?

i forget which long-time member here i heard this from, but: "when in doubt, wait". no matter what the issue or concern is, chances are very good that giving the beer more time will make it better. so RDWHAHB and let the yeast do their thing. they work on their own schedule

 

[1Mainebrew]

I do agree that extended primary does lead to cleaner beers, but then again, I must say that I feel that is more of a result of age than contact with the cake provided that adequate pitching rates, oxygen and temperature were adhered to. By controlling these things, the beer is usually very clean right out of primary-fairly early I might add. Good process really does enhance things. Aged beer always tastes better, regardless of primary, secondary or keg.