How to remove acetaldehyde from Pilsner

[bd2xu]

I brewed a Czech Pilsner on April 15, OG 1.050. Used 2 packs of fresh Wyeast 2278 with a proper starter (used yeast calculator) on my stir plate, oxygenated with O2 before pitching as always. Had a strong fermentation at 50 F, on 6/27 I moved it to 68 F for diacetal rest for 3 days, it was measuring 1.010 and tasted good. I then (6/30) racked to a keg and dropped to 34 F and turned CO2 to 10 PSI. Beer tasted good cold.

I need it for a party on 8/27. I tasted it this weekend to see how it's progressing and HUGE green apple smell and taste, has to be acetaldehyde. Have never experienced this in my ales (about 150 batches) or lagers (this is my 10 lager or so).

What can I do (if anything) to get rid of the green apple taste and smell by 8/27??? Am I screwed? Had HIGH hopes for this beer!

 

[Callacave]

Had the same thing happen to me using W-34/70 a couple of times. Along with the obvious acetaldehyde created by the yeasts, I've also been reading about the affect of oxydation of ethanol that turns it into acetaldehyde, which I think was part of what was going on in those brews.

I don't have any answers, but I'm curious at other responses. I'm guessing that with a light style like Pilsner these types of off flavors are much more apparent. It's definitely making me look at my process, and how to avoid as much O2 as possible.

 

[bd2xu]

Well what do you know, I tasted this on Friday (today is Monday) and had huge green apple smell and taste. Just tasted again and it's dissipated a LOT, still there a little but now it's something I would serve at least! Hoping over the next 12 days it will clean up more. I do have it at about 34F and on 10 PSI CO2. Should I warm it up to get the yeast (whatever is left in keg from 1 racking) more active for the next week?

 

[dmtaylor]

Acetaldehyde is a chemical compound that boils at 70 F. If you warm up the keg and purge the gas a couple times a day for a few days I bet you can get rid of it.

 

[ParanoidAndroid]

Did you use distilled or RO water by any chance? Ive read that a lack of zinc in the wort can cause acetaldehyde to form.

 

[ChelisHubby]

Acetaldehyde is a chemical compound that boils at 70 F. If you warm up the keg and purge the gas a couple times a day for a few days I bet you can get rid of it.

If I understand what you said then if I warm the keg to 75 and have airlock on it most of the acetaldehyde will evap or boil off.

 

[bd2xu]

Did you use distilled or RO water by any chance? Ive read that a lack of zinc in the wort can cause acetaldehyde to form.

I did! Started with distilled and added to it to make soft water for a Czech Pils. Used Bru'n water.

 

[ParanoidAndroid]

I did! Started with distilled and added to it to make soft water for a Czech Pils. Used Bru'n water.

Have you ever had that problem before? Some wyeast nutrient might help if that's the cause of it. It's the only nutrient that contains zinc. Ive heard of people adding zinc tablets also.

 

[dsaavedra]

Huh, same exact thing happened to me. I bottled a Czech style pilsner that I had left in primary for 2 weeks at 51° and 2 weeks at 68°(so plenty of contact with yeast cake for "cleaning up"). Tasted good on the day I bottled, if not a little yeasty from the carboy being moved around. Then I tried one after 7 days in the bottle, as my impatient self often does, knowing full well it wouldn't be nearly "done", I just wanted to see how it was carbonating. I put my nose to the glass and BAM! Apples. Take a sip and it tastes like I am drinking applesauce. I had to pour the glass out. I'm really hoping that 2 more weeks in bottles at room temp and a month in the fridge will take care of it.