Acetaldehyde Fix Post Kegging (adding more yeast?)

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:


New Member
Oct 10, 2021
Reaction score
Hi all,
I brewed a Kolsch recently (recipe that I have done successfully many times in the past). My yeast starter (Wyeast 2565 Kolsch) seemed low in activity but I was in a rush so I pitched anyway. After 3 weeks and monitoring SG until it finished fermenting I kegged it. It has a slight green apple off flavor which, coupled with the potentially low cell count in the yeast starter, I believe to be acetaldehyde. I have not carbonated the beer yet, it is in the keg at room temp sealed with 10PSI of CO2 in the hopes that remaining suspended yeast will clean up the acetaldehyde.

I am wondering if there is any way to fix the acetaldehyde at this point?Would getting another yeast starter going and pitching in more yeast help absorb the acetaldehyde?



It ain't all burritos and strippers, my friend.
Aug 24, 2010
Reaction score
I'd say you're on the right track, keeping it at room temp to give the yeast a chance to clean up the acetaldehyde. But you really don't need 10 psi to keep the keg sealed. A couple PSI would do it, and might be easier on the yeast.