Acetaldehyde and Lagers Boil-off at 68.4F?

[RCCOLA]

I brew mostly lagers, build RO with minimal additions, check and adjust pH, ferment in a temp controlled chamber and pitch adequately sized starters using yeast calculator software. Allow temp to rise at the end of ferm/sit on the cake awhile,blah, blah, blah.

Even though I do everything as I should, I still had one end up appley awhile back. I got to researching and found info that acetaldehyde boils at 20.2 °C/68.4 °F.

It struck me that letting my beer sit at 70F for a few days before lagering might be a good strategy to ward off the Jolly Rancher Special.

So, with this boiling temp at 68.4 F, can acetaldehyde escape the beer and exit an airlock? How long a time frame would one of you sciencey-summaguns® estimate off-gassing to occur?

TIA, all replies welcome.

 

[ajdelange]

Even though I do everything as I should, I still had one end up appley awhile back.

If your beer tastes of acetaldehyde at above the hint level then the problem is probably infection. The fact that this happened to you once suggests that infection may have been the cause.

I got to researching and found info that acetaldehyde boils at 20.2 °C/68.4 °F.

It does. Try to pipet it some time.

It struck me that letting my beer sit at 70F for a few days before lagering might be a good strategy to ward off the Jolly Rancher Special.

This is called a 'diacetyl rest' because the extra activity of the yeast at this higher temperature speeds its ability to clean up diacetyl and acetaldehyde.

So, with this boiling temp at 68.4 F, can acetaldehyde escape the beer and exit an airlock? How long a time frame would one of you sciencey-summaguns® estimate off-gassing to occur?

For an uninfected beer diacetyl and acetaldehyde are both reduced to below objectionable level during the course of normal lagering. One of the most interesting things about lagering is that the Jungbuket hangs in there for perhaps two - three weeks and then disappears over night.

TIA, all replies welcome.[/QUOTE]

 

[RCCOLA]

AJ, I've always done a d-rest at the end of ferm but never let my chamber rise above 65F. It occurred to me that my winter brews won't reach 70F w/o heat. All I need do is plug a bulb into the heat side of the STC.

My one batch lost 95% of its apple after lagering but it was still picked up faintly by 1/3 BJCP judges. I couldn't tell it except after reading the notes--went back and tasted for it.

Currently have a Světlý Ležák 12° sitting at 22°C after a 10°C ferment. Thinking about letting it sit at this temp for ~7 days before the cold crash. Sound like a good strategy?