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Howdy folks. I’m making a bourbon using yellow label angle yeast (YLAY) for the first time. I mistaking covered the ferment the first night and the temp was up to 110F the next morning. Uncovered it took a day for the temp to drop to 95F. I’ve read that a high temp can add some off flavors, and of course I’m concerned that the yeast colony may have been damaged by the high temp. Anyone think I need to pitch some bakers yeast now that the temp is down, or do you think the yeast will be fine now that the temp is back within a descent range?

Grain bill:
68% flaked corn (57 lb)
21% malted barley (18 lb)
11% malted rye (9 lb)

Added rye to 12 gal of boiling water, sit for 2 hours. Add other grains and water to 40 gallons at 95F, ph 5.75. Pitch 200g YLAY.

On a side note I have to say “Where have you been?” to my new transfer pump. Another first for me, using a transfer pump, and I have to say that it is now one of my favorite tools. Moving liquid has never been so easy, nor as quick. No more lifting, dealing with different elevations or transfer buckets.

Otis,

I can't comment on the temp tolerance of YLAY but you might just wait to see how ferment activity resumes (or not). One option: you could always add some gluco and bakers if you think they would push the slower-working YLAY to the side and take over.

I would be interested to see which transfer pump you have.

I read somewhere recently that YLAY can tolerate 104F early in the fermentation, but I can't find the source now. I'd let it go a few days and see if it continues to work.

Early last year I made 2 bourbons that I barreled in 6 qt Badmos on 5/16. Identical grain bills (70% cornmeal, 22% flaked rye, 8% barley malt) - #13 was mashed using standard method and FS917 yeast, #14 was made using YLAY. Both were pot stripped, and run thru a 4" column with 3 sieve plates.

Last week I had a free afternoon all to myself, so I thought I'd sit on the patio with a bourbon, cigar, and a book for a few hours. I first had #13 at cask strength with 2 small ice cubes - a very nice, light, spicy, young bourbon. Then #14 the same way - very similar but slightly different. I'm pretty happy with the results of the YLAY batch.

I don't know what I'd do without my transfer pump. I've used it since Day 1 of this new adventure. I had it for about 20 years for my homebrewing, so it was natural to continue using it. Mine is a March Hi Temp with magnetic coupler to an SS pump head, but this model probably isn't made any more. It doesn't do great with boiling liquids (cavitation) but a ball valve on the output can be used to restrict it a bit to stop cavitation.

I've done a similar thing, that yeast can generate some serious heat when first pitched.
I'd leave it be and see how it goes.
The extra heat didn't seem to effect mine long term.
Just punch the grain cap down and see how quickly it forms again.......if it's too slow you might have a problem.

OtisT wrote: ↑Tue May 06, 2025 6:44 am On a side note I have to say “Where have you been?” to my new transfer pump. Another first for me, using a transfer pump, and I have to say that it is now one of my favorite tools. Moving liquid has never been so easy, nor as quick. No more lifting, dealing with different elevations or transfer buckets.

For me it’s the opposite, ”Where are you?”. My brewing pump is one of the things I just cant find after I restarted my brewing hobby this winter. I’ve looked everywhere but up to now no luck. I loved that thing! But sooner or later it will show up, probably one week after I succumbed and bought a new one.

OtisT wrote: ↑Tue May 06, 2025 6:44 am Howdy folks. I’m making a bourbon using yellow label angle yeast (YLAY) for the first time. I mistaking covered the ferment the first night and the temp was up to 110F the next morning. Uncovered it took a day for the temp to drop to 95F. I’ve read that a high temp can add some off flavors, and of course I’m concerned that the yeast colony may have been damaged by the high temp. Anyone think I need to pitch some bakers yeast now that the temp is down, or do you think the yeast will be fine now that the temp is back within a descent range?

I'm inexperienced with YLAY but I do know yeast can tolerate higher temps at first when not much alcohol is present.
Once the fermentation is underway, the temp tolerance drops significantly as the alcohol level rises.
Me, I'd wait and watch, if the ferment doesn't keep going. I'd pitch some hydrated bakers or K1-V1116

Thanks for the input. I think the ferment is fine after my initial panic. The temp has been slowly dropping from 95F to 88F now. Slow but consistent bubble on the bubble cap. I stirred yesterday morning and my cap came back fairly quickly, thought the cap has been really thin on this batch all along. I’m going to put a lightbulb in the insulated ferment box today to prevent the temp from dropping further.

higgins wrote: ↑Tue May 06, 2025 8:19 am f, so I thought I'd sit on the patio with a bourbon, cigar, and a book for a few hours.

Congratulations on having the perfect few hours. You won the day.

OtisT wrote: ↑Thu May 08, 2025 4:54 am Thanks for the input. I think the ferment is fine after my initial panic. The temp has been slowly dropping from 95F to 88F now. Slow but consistent bubble on the bubble cap. I stirred yesterday morning and my cap came back fairly quickly, thought the cap has been really thin on this batch all along. I’m going to put a lightbulb in the insulated ferment box today to prevent the temp from dropping further.

Yeah you'll be fine I've done the same with ylay, put it to bed wrapped up and checked next morning to find it's risen over the official Max temp tolerance.

Just make sure you keep punching the cap down to attain max conversion from the grain, I do 3 times a day until it noticeably slows.

Twisted Brick wrote: ↑Tue May 06, 2025 7:18 am I would be interested to see which transfer pump you have.

It’s a Ferroday Wort Pump. Just a little cheep model. I added quick connects to the threaded ends.
.
PS. The ferment is done enough. The bubbling has stopped. Gravity is at 10 00 now, temp adjusted.

I see a mop bucket in my near future.

OtisT wrote: ↑Fri May 09, 2025 8:15 pm

Twisted Brick wrote: ↑Tue May 06, 2025 7:18 am I would be interested to see which transfer pump you have.

It’s a Ferroday Wort Pump. Just a little cheep model. I added quick connects to the threaded ends.

Thank you. That looks perfect for our application.

OtisT wrote: ↑Fri May 09, 2025 8:15 pm
.
PS. The ferment is done enough. The bubbling has stopped. Gravity is at 10 00 now, temp adjusted.

I see a mop bucket in my near future.

That seems fast. My YLAY bourbons take about 2 weeks to finish. I don’t believe the SG is a good indicator IMHO as the conversion continues to occur throughout the process. I watch activity. How does it smell? Mine usually starts to smell pretty foul around the one week mark, then cleans itself up. Most of my recipes are wheat, oats and rye so haven’t done barley. Wondering if the wheat is responsible for the odor.

I concur with Dougmatt, forget SG when using YLAY. The starch is being converted to sugar at the same time as the yeast is consuming it.
If the cap has dropped to the bottom and it's starting to clear at the top, dip your finger in, if it's sour it's done.

I agree with the previouse two posts, and it does seem fast....has the cap sunk completely?

Thanks for the input folks. This is why I posted this, to get help with something new to me.

I’ll let it go until next weekend. With the nice mild weather here, a 40W bulb has been holding the temp steady in the insulated box near 88F.

I do still have a thin cap coming back after pushing down. It don't smell bad yet, but the smell does seem like its starting to turn. I’ll give it a taste tonight to see how sour it is.

If the cap is still rising, it's being pushed up by co2, it's not finished.