Yeast Question

Hello,

I have read in several threads that if a beer is given sufficient time on the yeast cake, the yeast will clean up some of their waste and create a better tasting beer. I have an IPA that has been fermenting for ten days now and it is still bubbling (albeit slowly now). Even though the brew is still bubbling, is the clean up process described above still taking place? In other words, when this clean up process is occurring, is CO2 evolved or not? Even after it is done bubbling, should I still give it a week on the yeast cake before transferring? I want to rack to secondary but I don't want to do it too early and fail to receive the benefit of the clean up that occurs when the beer sits on the yeast cake. However, I also don't want to leave it in my ale pail for too long and risk oxidation.

Thanks in advance for your help!

If you're worried about oxidation after 10 days, you really need to RDWHAHB.

Leaving a beer on a yeast cake, the biggest threat is autolysis, not oxidation. Don't let that scare you away from extended primaries, it takes months before autolysis becomes a threat. I leave my beers in the primary for 4-8 weeks, and have never gotten even a hint of autolysis. Anything less than 3 months, you really don't have to worry at all.

As for the CO2, any time the yeast are eating, they're producing CO2. Even after they're done, some CO2 is still left in suspension, and it takes a little while for it to gas off. After 10 days, the yeast are still cleaning up after themselves. If you want to go with an extended primary, leave it for a total of 4 weeks, check the SG, and bottle or keg from there.

Ive found so far, that for most beers, its best to leave it on the cake 3-4 weeks before racking or bottling. The extra time has made a considerable difference in my final products. Leaving it on the cake shouldn't cause oxidation because there shouldn't that much oxygen in your bucket at all. During fermentation, its pushed out through your airlock and replaced by Co2. So even after your airlock stops, you still have that Co2 cloud protecting it. I say wait as long as you can stand it.