Higher initial fermentation temperature

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Ninoid

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I don’t have fermentation temperature regulation and my beer ferments at room temperature. Now comes winter and colder weather, so the room temperature is lower, and I would like to use Saison Mangrove Jack yeast M29, which ferments at temperatures from 26'C to 32'C.
I have an idea to cool the wort to 30'C and pitch the yeast even though the room temperature is a little above 20'C.

What do you think about that?
Would I get as good a beer as in the summer when my room temperature is around 30’C?
What about diacetyl rest?
 
I would not pitch at 30C...too high IMO, and a recipe for a fusel bomb. If you want to take a saison that high, it's much better to pitch low and ramp up. The good new is that this yeast should work just fine (though a little slower) at 20C or a little higher, in spite of what range might be listed on the vendor's web site.

ETA: Regarding a diacetyl rest... You probably won't need to do one. But there's nothing that happens in a D-rest that wouldn't also happen with extended time at lower temps, assuming the yeast don't actually go dormant (unlikely).
 
Because I can't regulate the temperature, all I have to do is try pitch yeast at a lower temperature, a little over 20'C.
 
I've always followed advice that recommended holding temperature on the low side for the initial fermentation of a Saison then letting it 'free rise' under its own 'steam' once fermentation takes off. It's surprising how much heat an active fermentation kicks out. Exploit it! Without any temperature control, I'd pitch at a lower temperature and insulate the FV to let the yeast build up the 'heat' to push a Saison along. This is something I tend to do regardless, e.g., with my English ales. I think the main focus here, for you, is to ensure the FV is sufficiently insulated and pitch the yeast into wort at (or just below) the recommended lower temperature limit for the yeast you're using. What you don't want is the external/environmental temperature dropping to impact yeast behaviour negatively, especially this time of year. At least for me, where autumn is rolling in with subzero nights forecast 🥶
 
I will follow the weather forecast and then brew when it warms up a bit.
 
There are always ways to achieve what is necessary. You can make a tent around the fermenter and put a heat source inside there. A low wattage light bulb 10-25 watts, covered by a coffee can for example.

Fermentation temperature profiles, regardless of the strain should be colder to hotter over the course of the ferment.
 
It is very easy to control temp up if your cellar is too cool. A inkbird 308 and a fermwrap or similar heater with a little blanket or some bubble wrap does the trick for low effort and money.

Even before I made a glycol chiller, I made many batches w good temp control in cellar that was a little too cool in winter for lagers, and a little too cool in spring & summer for the ale yeast I use.

I'll go slightly against common wisdom on pitching yeast when wort is just a little warm, but soon to cool. Before I had chiller, I would pitch after pumping to fermentor without any noticeable ill effects on taste, mind you, wort would be cooled into optimal temp range by the time the yeast got going.
 
It is very easy to control temp up if your cellar is too cool. A inkbird 308 and a fermwrap or similar heater with a little blanket or some bubble wrap does the trick for low effort and money.

Even before I made a glycol chiller, I made many batches w good temp control in cellar that was a little too cool in winter for lagers, and a little too cool in spring & summer for the ale yeast I use.

I'll go slightly against common wisdom on pitching yeast when wort is just a little warm, but soon to cool. Before I had chiller, I would pitch after pumping to fermentor without any noticeable ill effects on taste, mind you, wort would be cooled into optimal temp range by the time the yeast got going.

That's my plan, too.
Pitch the yeast at a slightly higher temperature so that it cools down a bit more until the yeast starts to ferment and so that the yeast itself maintains a temperature about 5'C higher than the ambient temperature. I think it could pass without consequences for the beer, but what worries me a little is what when the yeast activity starts to drop and the fermentation temperature equals the ambient temperature? Will diacetyl be cleaned in that case as well?
 
Depending on yeast and actual fermentation temp, you may or may not end up with diacetyl.

If you add capacity for heat side of temp control, it is easy to set temp up for the D rest. I do this regularly w lagers in the winter, ferment in the low 50's F then keg and bump up temp to low 60's F for spunding and D rest. Alternatively, if you want to ferment it all the way out in fermentor, put heat wrap on that.
 
I think it could pass without consequences for the beer, but what worries me a little is what when the yeast activity starts to drop and the fermentation temperature equals the ambient temperature? Will diacetyl be cleaned in that case as well?

The good new is that this yeast should work just fine (though a little slower) at 20C or a little higher, in spite of what range might be listed on the vendor's web site.

Regarding a diacetyl rest... You probably won't need to do one. But there's nothing that happens in a D-rest that wouldn't also happen with extended time at lower temps, assuming the yeast don't actually go dormant (unlikely).
 
It is true that I never cared about diacetyl rest. Since I don't have fermentation temperature control, I couldn't. However, I have never even pitch yeast at a temperature higher than a few degrees of Celsius than ambient.
 
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