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Frozen Munich Helles


Grandmaster Brewer
Jun 9, 2011
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Is there an award for beer-brewing stupidity? If so I nominate myself for it.

Yesterday I decided to untangle the rat's nest of electrical cords in my carport, including the line to my beer fridge. Of course I failed to plug the fridge into the temperature controller. This morning the fridge was at 20 F. My 3-day old, triple-decoction Munich Helles had just started fermenting nicely at 50 F, but this morning it was frozen. The four kegs in the bottom did not splash when I rocked them.

I'm not too worried about the kegged beer. I assume it will thaw and accept the chilling with little damage - it should settle out any suspended yeast or other haze. But, the Munich Helles! Even if the fermenter (a plastic conical) isn't frozen solid, is all the yeast going to be dead? What should I do to rescue it? Can it be saved?

Back in 2009 MaltLicker said "...but never freeze yeast." Rep, Wildrover, and CR had an interesting discussion in early 2010 about brewing from a partially-frozen package of liquid yeast. Their conclusion seemed to be that there would be some surviving yeast. Others have said it is possible to freeze yeast for storage, but to expect high mortality and count on having to build up a starter from it.

My options seem to be: 1. Bring it back to 50 F and see if it will come back to life? 2. Bring it back to 50 F, agitate it and see if it will come back to life? 3. Keep it frozen while I rebuild a starter (fortunately, I have another pack of Wyeast 2308), bring it back to 50 F, agitate it and re-pitch?

Pending better advice, as soon as this is posted I'll start building a new starter. Hopefully, someone out there has a solution or two. I'd hate to lose all the effort I put into this batch.

Thanks for any advice.


Forum Moderator
Grandmaster Brewer
Aug 25, 2008
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durrettd said:
Back in 2009 MaltLicker said "...but never freeze yeast."

Man, I feel like I've been fact-checked.org'd or something.  I guess I meant "on purpose" like a yeast-storage strategy? 

Some people rebuild vast quantities from tiny slants, so anything is possible. 

The Helles.........assume 48 hours of happy ferm time......probably some alcohol present.  With wort back up to 50F, I'd just create a new lager-sized starter and pitch it at high krausen so it is actively eating.  It "should" fit right in and do a decent job.