Help needed : near freezing temperature during lag phase.

[Drackean]

Title says it all. I started my freezer-converted fermentation chamber without noticing its probe was hanging outside of it yesterday afternoon. I came back late in the evening to realize the thing kept running for about 8-9 hours, chilling my precious brew all the way down to the 32F range. The wort is now back to about 66F since morning and is not showing any sign of fermentation. I gave it a good swirl this afternoon.

Am I screwed ?

 

[day_trippr]

Oh hells no, you'll be fine. I store yeast at a set temp ~36°F so you know they see even colder temps yet they always perk right up and do their thing...

Cheers!

 

[cjgenever]

Just swirl every so often to get the sleeping yeast into suspension as they wake. You're all set. The mass of the wort protected the yeast from thermal shock.

 

[Drackean]

Thank you guys, I feel a little better. I aim for a fairly clean pale ale though : could this stress the yeast enough to cause unacceptable levels of esters ? Will all this shaking cause some oxidation in the final product ?

 

[day_trippr]

Fermentation was still going on before the yeast went to sleep, so the head space was probably CO2-rich. I don't think you need to worry about oxidation.

As for adverse ester formation, you didn't mention what yeast you used, but some will indeed exhibit atypical characters when run cold versus run in their wheelhouse (eg: US-05 tends to throw peach character below mid-60s)...

Cheers!

 

[Drackean]

I'm using US-05. Let's hope that peach character doesn't come too strong.

 

[cjgenever]

I had a peach apa once from too low a ferm temp with us-05. Was actually kinda good