Acetaldehyde problems ?

[Dland]

Just did a trub dump on last weekend's brew. Third batch in a row to be undrinkabley sour. First time around I assumed infection, so everything was sanitized even more than my thorough procedure, then the next batch, same sour taste. Did some research on this forum and elsewhere, & started suspecting the dreaded acytaldahyde, as cellar was warmer than usual, partly due to heat wave, partly due to having shop space above it open a lot working on trucks.

Cooled the cellar down to 69F for last batch, but fermentation temp still hit 74.3 during height of fermentation. These batches all started out around 1.054 SG, pitched with fresh US-05 each time.

The first two batches I kept working, the first in kegs, the second is still in a conical, as is third. Despite some yeast activity, any improvement has not been enough for me to want to drink the stuff. Guess I'll be dumping 30 gallons of sour beer. Is it likely that there is too much acetaldahyde for yeast to clear it? I'm guessing there is no way to clear it, and it does not seem likely to age out.

I brewed similar ales all last summer, and they were fine. Unfortunately I did not keep temp records last year during ferment the way I always do with lagers.

Seem to have hit a wall here, never had two bad batches in a row, let alone three, running low on beer, I guess I may have to give up brewing until I get better temp control or weather turns.

It occurred to me that it could be a bad batch of yeast somehow(seems unlikely with Fermentis), but I found the empty packets in trash and one of them is from a different batch than the other two.

Any insights or suggestions? I know I should invest in fermentation temp control, funny, about 3/4 of the brews I make are lagers, which I brew when it is cooler, and have not needed it.

 

[Smellyglove]

If it's undrinkably sour I'd say that it's more likely you have an infection. Acetaldehyde just gives you a "green apples/pears" -thing. Us-05 has also a wide temp-range before it goes south. If the last beer was noticable more sour than the first one of the three, then it's most probably an infection which is evolving in the system.

Have you taken apart everything in the BK as well? Threads are notorious bug-harvesters.

 

[Dland]

I have not ruled out infection, but have not found source. The wort leaves BK at around 200F. I don't see how infection could start there. If anything, the first batch was worst. Everything post boil gets PBW/Starsan before use, plus Iodophor rinse before being put away, two different fermentors involved. It does occur to me I could be picking up infection due to C keg fitting I use for closed transfer, which I started doing recently, although that gets soaked in Starsan and valve opened before each use.

The only other variation I thought of is I cut back on oxygenating wort recently, but the yeast was quite active.

 

[corax]

I agree with Smellyglove: if it's truly sour (like in vinegar, lemon juice, or geuze) then I don't think acetaldehyde is your problem. It would almost certainly be a bacterial infection of some sort.

 

[Dland]

Yeah, all three batches crittered, the way I know for sure is if you taste them at all, like I did this morning, they will ruin my pallet for beer of any kind for at least a day (so you mise well drink those old elephants, first layer of SBR: Strategic Beer Reserve.) seriously though this sucks, 3 infected brews in a row, will have to buy beer for first time in a while and re evaluate all my processes.