Temperature Swings: What Have I Done to My Yeast

[sleepspeaking]

So I have a cream ale going, I used the Cream Ale Yeast Blend (White Labs #WLP080) and worked up a 2ml starter. But I didn't follow my fermentation schedule.

Everything was going fine, I was on my 9th day and it was hovering between 68°-70°. And then, for reasons even I am still trying to figure out, I brought it down to 42° where it has sat for the last ~48hrs.

Today I realized that I made a horrible decision and brought the ferm chamber back up to the 68°-70°. I also took a reading and I'm within the margins of my final gravity.

The questions are:

1) Should I step it up the the proper temp?

2) What have I done to the yeast, and in turn my beer?

3) As I plan to bottle this one, will I need to re-pitch? and if so will the 8oz of starter I saved work for that? or how should I go about that?

 

[slym2none]

That temp won't kill your yeast, just make them very sleepy. Sounds like they went back to work, according to your post.

I don't think you'll need to add yeast for bottling. Again, they didn't get killed off by the cold.

 

[mblanks2]

1) Should I step it up the the proper temp? Yes

2) What have I done to the yeast, and in turn my beer? Put them to sleep and nothing

3) As I plan to bottle this one, will I need to re-pitch? and if so will the 8oz of starter I saved work for that? or how should I go about that? No need to re-pitch

 

[joshesmusica]

So I have a cream ale going, I used the Cream Ale Yeast Blend (White Labs #WLP080) and worked up a 2ml starter. But I didn't follow my fermentation schedule.

Everything was going fine, I was on my 9th day and it was hovering between 68°-70°. And then, for reasons even I am still trying to figure out, I brought it down to 42° where it has sat for the last ~48hrs.

Today I realized that I made a horrible decision and brought the ferm chamber back up to the 68°-70°. I also took a reading and I'm within the margins of my final gravity.

The questions are:

1) Should I step it up the the proper temp?

2) What have I done to the yeast, and in turn my beer?

3) As I plan to bottle this one, will I need to re-pitch? and if so will the 8oz of starter I saved work for that? or how should I go about that?

Not a huge deal, as technically speaking, most fermentations are finished (including the clean-up phase) by around day 9-10. Luckily these extreme temp swings were at the end of fermentation. Next time, make sure you have your preset temps down before starting fermentation. If something like this happens in the first few days, you could actually have a disaster of a beer on your hands. This time around, though, you were lucky enough that it didn't likely ruin your beer. I would probably lager it for a week or two, and then bottle it. Then once carbonated, I would refrigerate the whole batch, and likely not drink the first one until about a week or so after that. With this type of beer, the lager it sits at lager temps, the better.

 

[Bosh]

Yeah that late the yeast are pretty much done anyway so no real harm.