Saison got too hot - at what temp does the yeast die off?

[TomFromEnfield]

I've messed up!

I had a saison fermenting that came down to 1.013. I thought that was a little high but it was at the lower limit of the attenuation for that particular brand of yeast. I wanted it a little drier though so pitched some Belle Saison into it and had it at 30 degrees. Things were coming along nicely and a week later it had dropped to 1.008. I think I must have knocked the thermostat at some point as I've just checked and it's up at 47 degrees! I'm guessing the temperatures been increasing for about 48 hours when I last went near it.

I can bring the temperature down gradually but does anyone know if I've killed off the yeast? Google implies the kill zone is above about 60 degrees but that appears to be based on baking yeast so I'm still unsure. Based on the last measurements the ABV is somewhere in the region of 6.5%.

If it is still alive, should I add another pack for bottling once it's cooled down a bit?

 

[dwhite60]

I know some saison yeast work better warmer. Not sure about 48 warm.

Cool it down and see what happens. Taste a sample. It's all you can do at this point. I wouldn't dump more yeast in at this point.

 

[foxy]

It is about 60 C for brewing yeast as well, its still yeast.

 

[TomFromEnfield]

Thanks for the responses. I was worried the alcohol might affect them at at lower temperature but the gravity has dropped right down to 1.000 so I think I'm okay. This was right at the end of the primary so hopefully I've gotten away with it, they only need enough vitality to go a little further once I've got them bottled. Belle Saison's upper recommended limit is 35°C .

 

[Pennine]

you are going to have some amazing flavors i think!

 

[TomFromEnfield]

Thanks for the responses. I was worried the alcohol might affect them at at lower temperature but the gravity has dropped right down to 1.000 so I think I'm okay. This was right at the end of the primary so hopefully I've gotten away with it, they only need enough vitality to go a little further once I've got them bottled. Belle Saison's upper recommended limit is 35°C .

I just realised that's 1.006 once the temperature is taken into account. It still appears to be coming down though.

 

[dad_of_jon]

I just realised that's 1.006 once the temperature is taken into account. It still appears to be coming down though.

go funky saison

 

[Wynne]

Fatal temperature for brewing yeasts is 37C for ale yeast and 34C for lager yeast.

 

[TomFromEnfield]

Thanks for the input. I've added some additional yeast.

 

[BeerCat]

I have fermented at 43c without any problem so i do not see an issue.

 

[strange-steve]

Fatal temperature for brewing yeasts is 37C for ale yeast and 34C for lager yeast.

That's very specific, do you have a source on that?

 

[Wynne]

A simplification. Happy to look up and post references but I have an exam coming up so it may be a few weeks.

 

[Harbey]

As has already been mentioned, I think it will be fine, just rather full of funky flavours. Saison yeast loves the warmth, perhaps not that warm, but I doubt it will have killed the yeast or the beer.

 

[TomFromEnfield]

Just to follow up in case this helps anyone else. I did pitch another packed of Belle Saison, I did that straight into the fermenter without building a starter. Nothing happened and the gravity didn't shift. So I boiled a little sugar in water, cooled that and added it to the fermenter to check for signs of life. Sure enough the airlock started bubbling so there's definitely life in there. The gravity didn't drop.

About a week later I skimmed the krausen from another batch of actively fermenting Belle Saison and added that in as well. Still the gravity hasn't changed. I'm going to get it in the bottles this weekend. I haven't tasted it yet but it's given me so much work it's going to get drunk one way or another and I'm confident that it's alive and that gravity isn't going to get any lower.