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Crash Chilling Rate

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Magro

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Hey,

I have a couple of questions related to an American Brown I just brewed.

The beer has finished fermentation and I am wanting to crash chill it. I've been told not to just drop the temperature of the fridge, but rather slowly drop it to avoid stressing the yeast and creating diacetyl.

My question is how quickly should I be crash chilling this beer. So far I have been dropping it by 1 degree whenever I walk past the fridge. But it occurred to me that I may be stressing the yeast as it's sitting at uncomfortable temp for say 4 - 5 hours. Is this the case? Am I at risk of off flavours.

Also how does the temperature of the beer effect the dry hop? What temp would be good for conditioning if I intend on keeping the dry hop in there for a week longer.

Thanks,
Magro
 

bum

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Looks like they're going to have to change the name of the method...
 

Wolfy

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It's 1.30am so I CBF re-reading the 'Yeast' book and finding exact references.
However - from memory - they suggest giving it a couple of days after terminal gravity has been reached before chilling. In addition, while it's better to lower the temperature slowly to avoid stressing the yeast, if you're going to be at or below about 4degC yeast activity virtually stops and so it does not really matter how fast your chill it.

As a result, after I'm sure fermentation has completed (and then give it a little more time to 'clean up') I just set my old fridge to the lowest temp it can go to, then let it drop as quick as it can - usually takes 24 hours to as cold as it goes - about 2degC.
 

Bribie G

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Stressing the yeast won't create diacetyl, it's already been created. However if you crash before the yeast has had a chance to clean up, then diacetyl can remain.

I'd go further and raise the temp to whatever you pitched the yeast at for a couple of days, then crash.
 

Thirsty Boy

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Crashing too fast can cause the yeast to poop out a bit of unwanted stuff alright. But to my knowledge its not particularly Diacetyl or other flavour active compounds, its a protienase that could maybe effect your head retention.

However, a home fridge is unlikely to be able to drop a fermenter fast enough for it to be a real issue. If you have your fermenter wrapped up in glycol lines... OK, then worry. But if you just have a fermenter sitting in a bog standard household fridge I wouldn't worry too much. Hell, I wouldn't worry too much anyway... might happen, might be an issue.... very probably wont be even if you cool as fast as you can.

If it really concernns you - throw a blanket or two over the fermenter before you turn the fridge temp down... that'll slow down the rate it cools at significantly and doesn't require you to keep dicking about with your controller. Going more slowly wont hurt, so if the time isn't an issue for you then slower is safer in absolute terms.
 

Mattress

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At the moment I don't have a fridge that I'm able to crash chill in. The one I was using now has kegs in it.

As the cold weather has now hit Canberra (Winter is coming) would it be OK to just leave my secondary fermenter out in the shed for a couple of days before kegging?

Temp is dropping down to below zero overnight, not quite this cold inside my shed though.


Thanks
 

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