Acetaldehyde

[NanoMan]

For reasons that are a longer story than I need to go into, a lager I'm brewing initially had a substantial amount of acetaldehyde. Yeast was not pulled prematurely; my process for lagers is 5 weeks at 50F, no ramp down, then crash. (but there was a process problem). The beer is still on the yeast. This is a brand new 8 Bbl pitch and this stain is prone to acetaldehyde. The yeast manufacturer assured me the yeast should clear it up, and in fact a week ago (21 days post brew) I noticed marked improvement in the flavor (a lot less acetaldehyde), and I also noticed a resurgence of fermentation via off gassing, so I'm assuming the yeast is active and is converting the acetaldehyde. Question: Aside from visible fermentation (CO2), is there any other test or way to determine when the reaction is complete? Clearly I do not want to pull the yeast too early!

Thanks for any insights.

Cheers!

[Ted Briggs]

"my process for lagers is 5 weeks at 50F, no ramp down, then crash"

So your making lagers without lagering, Might look into that.

[dick murton]

Assuming you are starting at 1048 (12P), try allowing it to rise up to 54 to 56 F once you have got the gravity down to about 1025 SG (6.25 P). Hold at that temperature for 3 - 4 days then when the time elapsed AND gravity is close to final gravity, cool down.