[quote=“rebuiltcellars”]Poor yeast health could contribute to problems with acetaldehyde, but I don’t see how the beer would get worse with time if that was the case. Unless you are just getting progressively more sensitive and annoyed by it. How old was the yeast when you pitched it, and did you make starters to wake it up and get it multiplying before the pitch?
Based on the symptoms, I would guess aceto bacteria and too much exposure to oxygen post-boil, but by your process description I don’t see how that could happen. Do you happen to have a lot of fruit flies around, and is it possible that the fermenters were not well sealed against them?
It might be time to bite the bullet and replace plastics and hoses.[/quote]
I’ve read a little about acetaldehyde today since that does seem to be what’s indicated by the green apple odor and off taste.
I don’t taste anything like cardboard that would indicate oxidation. The only possibility of oxidation would be hot side aeration but I’ve stirred while chilling on all my batches from the beginning so why would it rear it’s head now?
Everything I read re: acetaldehyde points to either high temp fermentation or racking off the yeast too early before clean up occurs.
The Innkeeper batch I noticed this in was racked to a keg after 11 days in the carboy. I had taken a gravity reading on day 8 and on day 11 both were 1.010.
With the latest one kegged yesterday, the amber ale OG was 1.071 and after 3 weeks in the fermenter it was 1.010 for a couple days in a row.
I followed the same temperature control measures as usual. Pitch at about 63, swamp cooler to keep temps in the 63-65 range for the first 3 days then let it rise, removing from the swamp cooler on day 5 or 6 and allow to rise to ambient of 68-70. It’s a bit cooler in my basement right now so final temp may not have gone above 67-68. Doesn’t seem like that should be a problem…
The only other difference over past brews was my grains. I bought grain from a new LHBS but they’re briess, rahr, reputable grains and seemed to be fresh.
So…all evidence seems to be pointing to my harvested yeast as not being pure or healthy…does it not?