Froze my beer in fermentor while cold conditioning!

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aidan

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I had read about it happening to others (John Palmer relays his experience freezing his lager in How To Brew), so I didn't cry when I discovered my frozen ale as I was about to bottle it this evening. But I surely did have to abandon hope of bottling it tonight. I had all my bottles sanitised and my priming sugar boiled when I went in to the fridge to lift out the fermentor of beer that I had been cold crashing for 5 days. I didn’t like the solid look that I saw from the outside and sure enough when I opened the lid, here is what I saw:
frozen.jpg


I had been cold crashing it in my fridge at the coldest setting. I had kept a close eye on it for the first few days for any signs of freezing. I even had a plastic bottle with a drop of water that I could check for freezing above the fermentor and another one below and there was not a sign of any freezing in those first few days. So than I got complacent and put too much trust in my fridge and left it at the low setting until the bottling day that didn’t happen.

It’s not frozen solid, it’s liquid towards the bottom, but it’s hard to tell how frozen it is. I took a sample from the tap, tasted it and it was super sweet – it measured an SG of 1.032. It must be because it’s the water that’s frozen out first leaving concentrated beer at the bottom.

So now I’m leaving it out at room temperature over night and when it’s defrosted I’ll give it a bit of a stir around to get it evenly mixed again and then I’ll give it a day or two to settle before bottling. I’m hoping the yeast in it is ok enough for carbonation as I don’t have a spare packet of yeast to match the kit yeast and throwing in a different yeast strain could possibly do more harm than good. So I’m not too worried about it, I reckon she’ll be alright - what do you think?
 
Was it done fermenting at 1.032? I wouldn't think that concentrated beer would taste sweet at all.
 
If your gravity seems normal once it thaws I would pitch a packet of something neutral like Nottingham or Coopers just to make sure it carbs up. If its done fermenting, the yeast won't give off enough esters to cause any flavor profile change.
 
Yeah, I would expect the concentrated beer to be drier rather than sweeter.

It would be sweeter because the residual sugars would be more concentrated.

I am not sure that fermentation was complete in the first place but that will have to be determined once it thaws.

I also agree that you should add some more yeast. It is likely that you froze and killed a good portion of the yeast so you may experience slow carbonation or no carbonation in some bottles.
 
It would be sweeter because the residual sugars would be more concentrated.

I am not sure that fermentation was complete in the first place but that will have to be determined once it thaws.

I also agree that you should add some more yeast. It is likely that you froze and killed a good portion of the yeast so you may experience slow carbonation or no carbonation in some bottles.

I agree! I'd just get a package of dry nottingham (no need to "match" the strain) and put 1/3 of a package of it in the cooled priming solution. Or pitch the dry yeast when the beer warms up, to see if it'll ferment a bit further.

No need to stir the beer, either, once it thaws- you don't want to introduce oxygen. I'd probably just keep it covered and gently swirl it. Racking it to the bottling bucket will help mix it too, especially if you start the siphon in the middle, and gently rack from the top/bottom/middle just by gently moving the racking cane.
 
Before I froze it I had measured SG of 1.018 for 3 days straight (it was fermenting for 2 weeks - slightly higher than target of 1.015 but close enough I reckoned. I am assuming the sweetness I tasted is the result of the concentration with a lot of the water being frozen out of it. When I checked it this morning there was still a big chunk of ice floating inside it and it went quite deep so I reckon it was pretty well frozen.

Thanks for advice on not stirring it, I had planned on stirring it gently to get it evenly mixed but I guess you could be right about introducing oxygen. I did stir it a bit and broke up the ice block with a spoon this morning so I hope I didn't cause too much oxygenation.
 
Do you think I need to bring the temp up to 65F before pitching additional yeast? or should it be ok to pitch once the ice has all gone?
 
You can bottle cold. Pitch the new yeast into the bottling bucket, even if it's cold. But, make sure to bring the bottles to > 70 for a week to get them carbed, Under 70 can greatly increase the carbonation time. > 70 and it only takes a week.
 
You can bottle cold. Pitch the new yeast into the bottling bucket, even if it's cold. But, make sure to bring the bottles to > 70 for a week to get them carbed, Under 70 can greatly increase the carbonation time. > 70 and it only takes a week.

Cool, I'll be bottling straight from primary so I'll pitch the yeast into primary once all the ice has gone, give it an hour or a few to settle and then bottle it. I moved the fermentor up to the attic today where it is warm so hopefully it will be fully defrosted by tonight so I can go ahead with the bottling.
 
Well, I got it bottled last night. I put it up in the attic during the day to help it thaw out faster and it was fully thawed yesterday evening. I added another packet of yeast as recommended here. (I actually was able to get some Blackrock yeast which is the same brand as the kit). The SG of the sample I took from the tap at the bottom was 1.020 - a bit higher than the 1.017 that I had measured before cold crashing (er freezing), but I reckon it could have still been a bit more concentrated at the bottom of the FV. This time it tasted normal - not sweet like the post freeze sample. Since I added the priming sugar to the top it might balance things out a bit. Maybe I'll end up with some uneven carbonation but with plastic bottles there's no bottle bomb risk.
 
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