Fermentation temps got a little high

So, i went on a little road trip over the last 24 hours. I forgot to ask SWMBO to change out the ice bottles on my fermentation vessel. I got home tonight and the water bath was at about 74. I figure it was probably fermenting too warm for at least 12 hours.

My question is, How long does it take for damage to be done by high ferm temps? I pitched a fresh pack of US05 to this batch on Sunday evening.

Is it still actively fermenting (i.e. airlock activity)? If the beer is actively fermenting, so with a krausen/airlock activity/gravity readings dropping then the yeast are liable to produce off flavours. 74F tops out the acceptable range for US05, I think the documentations says 75F, so you should be just fine. How long do you usually leave the beer in the primary?

I think that if the main fermentation (before the krausen drops) is complete, the amount of off flavors is significantly reduced. But I know form experience that the first couple of days is critical. I've ramped up the temp after the hard ferment without major problems.

If the bath is 74, you can pretty safely bet the beer is significantly warmer. At least while fermentation is still active, anyway. I have had high temps screw up a batch in 24 hours - not sure if 12 would be enough to do it, but you'll find out

Gremlyn1 said:

Is it still actively fermenting (i.e. airlock activity)? If the beer is actively fermenting, so with a krausen/airlock activity/gravity readings dropping then the yeast are liable to produce off flavours. 74F tops out the acceptable range for US05, I think the documentations says 75F, so you should be just fine. How long do you usually leave the beer in the primary?

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Yeah, I brewed it on Sunday night. I ferment in SS pots so no airlock, but I can tell that it's going because I can smell it. I usually Primary for 2 weeks and then transfer to my Secondary for at least a week, but the last couple of batches I've let sit for 2 weeks in Secondary. I'm glad to hear that the range for US05 is that high, makes me feel better. Thanks.

Homercidal, your point is why I'm a little concerned. The first few days are definitely critical. I had a Kolsch that got too warm a while back, and it was definitely off, but that was with Kolsch yeast. I guess we will see in a few weeks.

Jester369 said:

If the bath is 74, you can pretty safely bet the beer is significantly warmer. At least while fermentation is still active, anyway. I have had high temps screw up a batch in 24 hours - not sure if 12 would be enough to do it, but you'll find out

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Yeah I figure it was probably 78-79 in the fermentor, maybe higher.

Unless your water bath is very small, I'm not so sure your fermenter will be that much warmer than the water bath. Mine covers about 1/3 of the bucket and usually doesn't vary by more than a degree or two (unless I've just added ice). US-05 seems to be a more forgiving dry yeast also. You're probably fine, not much you can do now anyway but get the temps back down and see how it tastes in a few weeks.