Temp Fluctuations during Cold-Crashing

[Gustatorian]

I was cold-crashing a beer in a conical and the temp went from 38 to 55 degrees overnight. I got it back down to optimal CC temps but I was wondering if this stresses the yeast out at all? Should I expect off-flavors? I wouldn't think so, since most have fallen out of the solution but just wanted to make sure.

 

[kombat]

Nah, they'll be fine. I'd bottle/keg that batch soon though, as you're sucking a lot of plain old air into that fermenter and risk oxidizing the beer.

 

[Gustatorian]

I know it depends on what strain, but what temp do ale yeast usually flocc out of beer?

 

[kombat]

All temperatures. But the colder the beer, the faster the yeast (and anything else) will precipitate out of suspension. Ideally, get it as close to 32° F as you can (or even a couple of degrees lower, actually), and things will clarify pretty quickly (a few days).

 

[Gustatorian]

Nah, they'll be fine. I'd bottle/keg that batch soon though, as you're sucking a lot of plain old air into that fermenter and risk oxidizing the beer.

Also, what do you mean by sucking plain old hair into the fermentor? How is that happening?

 

[kombat]

Each time you cool the fermenter, the air inside contracts, causing a slight vacuum effect that "sucks" in air through the airlock. Each time it warms back up, the air inside the fermenter expands and vents out the airlock. Every time this happens, the plain air coming in mixes with the air already in the fermenter (which is otherwise mostly just pure CO2), diluting the CO2 inside the fermenter with relatively-oxygen-rich air, and thus slightly oxidizing your beer.