Potential Fermentation Temperature Test

[VAbourbontester]

Thought I would share a potential experiment I am working on after a mistake in my fermentation temperature management.

Recently tried scaling up a whiskey recipe which I normally ferment in 5 gallon buckets. I know they don’t hold heat well at all which is fine in the summer where my garage is typically 80-90 degrees which is right in my yeast range (FSI-917 temp range of 80-93f).

Scaling up was my issue. I used an old 20 gal cooler which I obviously should have known would be better at keeping heat trapped. I also underestimated the amount of heat generated by increasing the volume of mash. Long story short I checked the temperatures yesterday and they were sitting at 103f and I assume have been there for 48+ hours.

Everything I have read indicates the yeast are probably going to be stressed to the point where the product is generally not drinkable. Input I would like from the community is what to do with it?

Is there any chance with enough time, oxidation and wood contact those compounds could change into something interesting? Or is this more like a scorching where I just cut bait, learn my lesson, and concentrate on running the rest of the mash that had proper temperature ranges.

My plan it to take the tried and true advice - run it and find out. But I would keep it as a stand alone batch. Unless it is pretty unanimous that I shouldn’t waste my time/seasoned wood.

Appreciate everyone’s opinion

[Wildcats]

Run it and find out. I dought it will be bad. Make good cuts. Will be interesting to see your results.

[Stonecutter]

Well what does it smell like? What’s it taste like? If it’s pleasant run it. Gotta keep your yeast buddies happy but if it smells and tastes decent you should be aight. If it smells like shit run it anyway and see what happens.

[zed255]

A yeasts recommended temperature range just indicates where it performs best. I sincerely doubt that 103F would have stressed the yeast to the point where it totally ruined the ferment.

Let it have a nice long rest, like maybe a week or two, to let the yeast clean up after themselves. Then run it and see what you get. Maybe you get a smaller heart cut. Maybe it will be a unicorn run. Find out.

[higgins]

A yeasts recommended temperature range just indicates where it performs best. I sincerely doubt that 103F would have stressed the yeast to the point where it totally ruined the ferment.

Let it have a nice long rest, like maybe a week or two, to let the yeast clean up after themselves. Then run it and see what you get. Maybe you get a smaller heart cut. Maybe it will be a unicorn run. Find out.

+1
I would run it separately.

If the white dog tastes OK then no problem adding it to the main product. Or even aging it separately.

If not, reflux it into neutral.

[VAbourbontester]

Well what does it smell like? What’s it taste like? If it’s pleasant run it. Gotta keep your yeast buddies happy but if it smells and tastes decent you should be aight. If it smells like shit run it anyway and see what happens.

Everything smells fine compared to the other containers that had proper ranges but when you taste between the two, you can definitely tell the one with the higher temps is sweeter.

[VAbourbontester]

I like the advice here so what I think I will do is:

1. Let the fermentation sit for a while longer to hopefully make use of the residual sugar I can still taste.
2. Run it separately with an eye towards conservative cuts with the option to go wider if it turns out ok.
3. If there is a difference between the main run then age separately, if no difference blend them in.

[Twisted Brick]

Please post any differences in your finishing gravities. If the 103F ferment doesn't finish dry (or close to it) you can always pitch more yeast.

One of the vagaries of fermentation is how much heat yeast produce when doing their work, and need to be adjusted for.

[jonnys_spirit]

Agree with the other suggesting to run it and see. It'll probably be fine.

I use an inkbird controller and wrap my fermenters with heat pads. If the temp keeps climbing I'll unwrap and hook a fan up to the cooling control. I have taken the lid off the fermenter with some sheer fabric over the top to allow more heat to dissipate too.

I have it in my head that one of these days I'll get either a glycol chiller or a coil/water-pump loop connected up to the cooling control to be able to do lower temp ferments with lower temp yeasties. I did purchase a copper wort chiller coil but I don't know how I feel about leaving a copper wort chiller in a mash/ferment for an extended period like 7-14 days or whatever it takes at lower temps... They do have stainless ones too and pumping a barrel of water through an active ferment is probably enough to prevent spikes before going to a dedicated glycol chiller system...

Cheers,
j

[Buffalo]

I had a couple of wash batches that just didn't smell good when the fermentation was done. When I decided to run them, the strip didn't smell too bad. After the spirit run it turned out ok. The bottom line is, what have you got to lose, just a little of your time and not too much cost in energy to run it to find out.
Good luck.

[8Ball]

If you are referring to FermSolutions FP-917 yeast, then you should be okay. I’ve used it in hot ferments with good results.

[shadylane]

Long story short I checked the temperatures yesterday and they were sitting at 103f and I assume have been there for 48+ hours.

Everything I have read indicates the yeast are probably going to be stressed to the point where the product is generally not drinkable.

Stressed, somewhat. But your making whiskey.
It will start cooling down now that the cap has fallen.

On a side note.
Yeast heat tolerance drops as more alcohol is present.
The final gravity will tell you how much you screwed up.

[Stonecutter]

Everything smells fine compared to the other containers that had proper ranges but when you taste between the two, you can definitely tell the one with the higher temps is sweeter.

Sweeter is a whole hell of a lot better than many other possibilities.
Give it plenty of time and try not to f*ck with it too much.

[VAbourbontester]

Please post any differences in your finishing gravities. If the 103F ferment doesn't finish dry (or close to it) you can always pitch more yeast.

One of the vagaries of fermentation is how much heat yeast produce when doing their work, and need to be adjusted for.

I didn’t get any finishing gravities but there was definitely some issue with the fermentation not finishing dry. After 5 days, just doing a taste test compared to those in 5 gallon buckets there were definitely unfermented sugars still present in the cooler.

I ended up pitching more yeast and leaving for another 3 days which finished everything up. I finally collected enough low wines for a spirit run so we will see how it tastes. I couldn’t taste anything different from previous runs on the low wines but I’m not sure that means much.

Lesson learned here for me was it is better to have very tightly controlled ferments in similar vessels, with smaller volumes than to try and juggle between two containers with different conditions.

[VAbourbontester]

If you are referring to FermSolutions FP-917 yeast, then you should be okay. I’ve used it in hot ferments with good results.

That was what I was referring to. It has done well for me so far.

[Twisted Brick]

Please post any differences in your finishing gravities. If the 103F ferment doesn't finish dry (or close to it) you can always pitch more yeast.

One of the vagaries of fermentation is how much heat yeast produce when doing their work, and need to be adjusted for.

I didn’t get any finishing gravities but there was definitely some issue with the fermentation not finishing dry. After 5 days, just doing a taste test compared to those in 5 gallon buckets there were definitely unfermented sugars still present in the cooler.

I ended up pitching more yeast and leaving for another 3 days which finished everything up. I finally collected enough low wines for a spirit run so we will see how it tastes. I couldn’t taste anything different from previous runs on the low wines but I’m not sure that means much.

Lesson learned here for me was it is better to have very tightly controlled ferments in similar vessels, with smaller volumes than to try and juggle between two containers with different conditions.

Well, at least you were able to finish up the ferment, narrowing the temporary stall to the batch of original yeast used (or maybe pH?). I agree - more control that you can exert over a fermentation, while a little more work, can translate to a finer spirit in the end.

Thanks for sharing.

[Demy]

Often you can manipulate the fermentation temperature to get a different product (a bit like it happens in beer)...a high temperature doesn't necessarily mean a bad product...obviously if you can control the temperature you will have control of the process

[shadylane]

Plus 1 on fermenter temperature control.

I use a jacketed fermenter and have a cheap STC-1000 that turns on a heater or cooling water as needed. The fermenter also does double duty for mashing.
Having accurate control of temp is worth the time and effort.

[ecir54]

shady do you do a thread on your fermenter setup?

[shadylane]

shady do you do a thread on your fermenter setup?

viewtopic.php?t=59138

[ecir54]

oh cool i have some reading to do thanks

[citywide]

Using same yeast on a 22 gallon batch of CROW bournon rn. I pitched last night and woke up to it at 103-4 degrees. Immediately unwrapped it and took the top off. Hopefully not too stressed!

[Saltbush Bill]

Point a fan at it to get the temp down faster.

[Bolverk]

If you got a wart chiller setup that should suck the heat out of it pretty quick