Aagh! It Froze!

With attribution to neither tool nor operator (though we all know which way the smart money goes), this morning I found my lagering freezer at 30F, well below the prior 35F set point. Somehow (see above) the controller’s brain got scrambled; it reported 100F set point and heating status, but the cooling relay was stuck on and the freezer was running.

Sometime between Tuesday evening and Thursday morning, my lagering WiesnGuy brew froze. Maybe not completely solid (the keg didn’t split and I did get a drop or two of liquid atop post when disconnected), but no flow on tap nor gurgle on shake.

HowToBrew mentions exactly this topic, but I may be near the seam of his recommendations:

“If you are towards the beginning of the lagering cycle, then there may not be enough yeast activity after it thaws to properly complete the attenuation and condition the beer. You should probably add new yeast. If you are at the end of the lagering cycle, and were planning on priming and bottle conditioning it, then you should probably add more yeast also. If you are planning on kegging it and force carbonating (like I was), then you don’t have to worry about it.” (my emphasis)

The beer was brewed Fri26Feb, fermented 50F to Thu10Mar, diacetyl rest 65F then racked to keg Sat12Mar to lager at 35F. OG was 1.052, racked at 1.012 very near FFT limit 1.010. Grain bill was 80% Pilsner, 20% dark Munich; about 25 IBU Hallertau. Yeast is WLP833, propagated second-generation reserved from prior starter.

This is a repeat of a favored brew that was frequently sampled (my very first lager!). IIRC (posting from office, notes at home) that brew was fairly OK after lagering 3 weeks but definitely better after 5-6 weeks and gelatin fining. I think most of the improvement was clarification and yeast “bite” reduction.

What should I do?

a) Should I let it thaw very slowly in kegerator space, or set it out to thaw more quickly? I doubt it matters, but ask while I’ve got your ear.

b) Is 1/5 lagering time reason enough to add more yeast, even though attenuation is essentially complete and I’m content to force-carbonate?

c) Should I add some pressure-canned wort to the fully-attenuated brew, to fuel surviving or added yeast?

Is (post-thaw) tasting likely to give information relevant to decide?

Either way, I’m gonna RDWHAB (alas, family party depleted inventory and RDWHAHB option). I really doubt it’s gonna be horrible whatever I do, I just want to minimize compromising a repeat of a brew I really liked.

Beer usually doesn’t freeze until it reaches about 27 degrees.

Having said that I suggest you take quick action. Drink it.

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I would let it thaw slowly at about 40°F. You may only be thawing the out tube. When you can draw a sample, taste it and check SG. Check again two days later in case the first sample may have been from slushy beer.

Oh, it froze alright, at least enough to neither flow nor gurgle. Freezer was 30F when I happened to look, but that might reflect both lag from the beer’s latent heat of fusion and warming leaked from the heated chamber fermenting my MarzenHerr brew (which held its 50F setpoint nicely).

Setup is a 10.6ft3 freezer (GE to operate to 110F ambient in Texas garage) with controller and 2x6 collar; room for 2 kegs and a 16"x18"x30" double-thickness cardboard box fermentation chamber with separate controller and heater heater (25*5W Chrismas lights painted black and shielded by foil). Both freezer and chamber have two muffin fans for circulation, always on. Fermenter is glass 6g carboy in stout milkcrate; pool-noodle foam secures carboy, pads crate handles, and insulates thermistor against carboy.

I never handle a filled carboy outside its crate. Lowering it over the freezer walls into the chamber is a bit of a vocabulary builder, but doable at 5’15" 240#.

Until I get a separate coolbox built, that lets me have up to three lagers in process. I’m trying to learn brewing lagers because that’s what I like to drink. I gotta admit, though, cold conditioning a cream ale or American wheat after cool 65F fermentation with US05 does seem to yield a pretty tasty and lager-like product for less time and effort.

You could always just dip out the ice and have an EisWiesnguy.

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I’m all for tasting (who needs a reason?) and I suppose I can endure delaying it long enough to measure gravity.

I already measured attentuation to 1.012 from the brew, essentially complete to the same-brew FFT 72+F endpoint limit 1.010. I wouldn’t really expect the lower-temperature fermentation to drop that last point or two, and even if so measured it’s reasonably within range of errors due to temperature correction and eyeballing my general purpose hydrometer that floats slightly off vertical.

So, what can a gravity measurement tell me, except possibly thaw confirmation (gravity increase suggests water bound in ice)? Not that that isn’t worthwhile… complete thaw might take days without moving to someplace warmer and stirring up all the clarification gained so far (possibly augmented by freezing).

I’m starting to think I should just step back, keep an eye on that errant controller (and its operator), let whatever happens happen, have a taste next week, and drink whatever I get whenever I get tired of hoping it will get better. If all else fails, there’s no shortage of beer-mooching friends that won’t know when they’re in beer disposal service mode.

Last year I had a bock lagering that froze completely, about 1 month into a planned 3 month lagering process. It was out in my cold garage and we had a spell of sub-zero weather. I brought the carboy inside and thawed it, then back out to the garage for another month and a half. I was going to reyeast at bottling time, but completely forgot. She carbonated well, and was absolutely wonderful. I have just a couple bottles left, waiting on my currently lagering 2015-2016 version. I’m rationing them carefully for the next 6 weeks or so.
So, I wouldn’t worry, and definitely wouldn’t be too aggressive on messing with her. She’ll turn out fine.

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I’ve froze a keg before, no biggie. Ended up being one of the clearest beers Ive made. It would have to be pretty cold for a while to crack a keg if you have a little head space. Just let it thaw. I just put mine in my fridge at 41 deg and thawed it there.