Too Cold During Fermentation

[Ltkenbo]

So a few weeks ago I brewed an IPA with some buddies. I have a chest freezer setup as a fermentation chamber to maintain the temperature. After fermentation was complete, I was planning on cold crashing the beer before dry hopping. I just used standard US-05 dry ale yeast.

Well, sometime before I got to that point (probably 2 weeks after), my temperature controller or sensor freaked out and thought the beer was way warmer than it really was and chilled it quite a bit. When I caught it, the actual beer temp was around 38F. So my cold crash happened for me, but I'm not sure if it ever got colder than that.

My only worry is that I'll bottle and that most of yeast has died off because they were potentially frozen and then I won't get any carbonation. Should I add some more US-05 before bottling to be safe? If so, how and when should I do it? A day before I bottle or something?

 

[Rev2010]

Honestly, unless you truly have reason to believe the beer went below 32 degrees I wouldn't worry about it. Even if it did I'm not too sure yeast cells would still freeze and expand at 32F in liquid beer (thus destroying their cells). And even if it did I doubt all the cells would be destroyed so I'd think there's probably still plenty enough to bottle carb.

Maybe someone with more experience on this can better give an opinion. If it were me I'd just bottle and condition and room temperature as I think it would still go fine. Perhaps rouse the yeast gently before bottling.


Rev.

 

[Keith81]

My guess is that you probably have enough viable yeast left for carbonation. The bigger concern would be wether the yeast finished fermenting the beer before going dormant from the cold. Take a hydrometer reading to see if you reached expected FG. You don't want to risk bottle bombs.

 

[Ltkenbo]

OK thanks guys. Yes fermentation should be complete. Actually it's been about 2 weeks since that happened (which was 2 weeks after beginning fermentation) and I've had it back up at temp with no change in gravity readings. I plan on bottling tomorrow.

 

[IslandLizard]

It should be OK to bottle. No need to add extra yeast, there's plenty left in suspension. If it had been sitting for 3 months or longer adding some yeast for bottling may be a good idea, and definitely after 6 months.