Did I kill my yeast?

[tomsen]

I have a batch of a munich helles fermenting and wanted to heat it up to 20°C for a D-Rest. Sadly I forgot to attach the temp probe so it heated all night up to 28°C...
Is there any way to tell if the yeast survived the heat blast? I used 2pkgs of W3470 and started the "d-rest" when I was a 1.012 SG.
Could I just repitch another sachet of w3470 to make sure it cleans up the rest of the process? Or will the normal lager process still work with dead yeast? will the beer flavour still improve from storing the beer for a couple of weeks?

 

[McKnuckle]

The yeast is not at all dead; quite the contrary! It should love that temperature, which is 82F. Of course it's not so good for your beer.

Luckily though, or at least hopefully, it is well past the point in your fermentation schedule where such a warm temp would produce off flavors and ruin the beer. Don't re-pitch or do anything like that. Don't open it, mess with it, etc. Just drop the temperature to an appropriate range, and then gradually lower to lagering temps. Allow for a proper cold lagering period, not rushing, and you should be able to forget all about this.

 

[Knkbrand]

I am not an expert at all, and I am sure there are more experienced brewers on here than me, but I think 28C is fine for the yeast. Not ideal, but also I don't think it killed them. They may give off a strange flavor, but it might also might make for a better D-rest. I wouldn't put it back in cold temps to bring it down quickly, just let it slowly come back down and I think it will be fine. I would say RDWHAHB, but I just got done freaking out about a yeast starter that wouldn't start. You should be fine. I wouldn't do anything to it other than let it slowly come back down.

 

[Tobor_8thMan]

28C (82.4F) is way high for 3470 yeast! 3470 temp range = from the package 9-22 C (48.2-71.6F) ideally 12-15C (53-59F).

Yeast, probably survived the "heat blast", but what mutations, fusel alcohols happened? I'd recommend sampling the brew. Taste OK? If so, proceed. If not, dump.

 

[Dinadan]

28 degrees C should equal 82.4 degrees F if I remember the conversion correctly. I do not think that will kill most yeast, but I do not have any specific knowledge about w3470.

 

[McKnuckle]

Folks, read the post. SG was 1.012 and this was a diacetyl rest, not pitching temperature or primary fermentation. And there is no way in hell that lager yeast DIES at 82F. In fact, maximum growth temp is 34C or 93F.

Saccharomyces pastorianus - an overview | ScienceDirect Topics

 

[dmtaylor]

It's just fine. No worries.

 

[Toto's]

If you have a temperature controler i would lower the temperature 2-max 3 degrees Celsius per day.....
Try to not lower the temperature in 1 day if possible

 

[tomsen]

Guys thank you so much. I will probably leave it at 19C for a couple of days and then lower it slowly for a cold crash. I understand now that yeast will easily grow at those temperstures, so no killing has occured. Thanks

 

[OldDogBrewing]

If I'm not wrong, yeast doesn't die until 48°C