"Hot" Fusel Alcohols

[I.P.EH]

Hey folks,
I am hoping to get some pointers with fermenting beers above 8% ABV. The last two recipes I have done with higher gravities have produced beers that have a lingering solvent / hot alcohol flavour. The first beer was fermented with Wyeast 3463 which can be a finicky strain from what I have read. I made a 2 liter starter on a stir plate and oxygenated the wort before pitching the yeast. I set the fermentation chamber at 19 C and let it rise to 24 C over a period of 10 days. Even after a month a half this beer showed no signs of dropping the hot alcohol flavor so I dumped it. Should I just give these beers more time or does somebody have a suggestion for how I could get a more healthy fermentation?

[darciandjenn]

What temperature did you pitch at?

Do you set an ambient temperature in your ferm chamber or do you have a probe that measures the actual temperature of the fermenting wort? Internal temps in fermenting wort can be several degrees higher than ambient due to heat produced by active fermentation...

24C is definitely on the high end for that yeast.

[Celiacbrew]

How did you oxygenate your wort? Too much oxygen can lead to higher fused alcohol production.

[I.P.EH]

I set the fermentation temperature to 19 C with the probe taped and insulated to the side of the fermenter. I ramped up the temp to 24 C after a week just to ensure fermentation was done but maybe I didn't give it enough time.

I use an oxygen tank with a stone to aerate the wort and I probably let it go for 90 seconds considering it was a big beer.

[Celiacbrew]

Do you know how much is flowing? Are there a lot of bubbles or are they just breaking the surface? 90 seconds doesn’t sound like it is too much but there was a brewstrong episode from way back where someone got fusels from 2 mins of O2.

[jason.loxton]

Maybe an under pitch? How big was your batch, how old was the yeast pack, and how did you treat your starter (stir plate, etc.)?

[jeffsmith]

Maybe an under pitch? How big was your batch, how old was the yeast pack, and how did you treat your starter (stir plate, etc.)?

This would be my guess as well, not enough yeast cells/stressed yeast.

[jacinthebox]

I'm gonna go with an under pitch of healthy yeast as well

[I.P.EH]

The yeast pack was about two months old when I made the starter but I pitched it after 12 hours on the stir plate which maybe wasn't enough time.

[oceanic_brew]

The yeast pack was about two months old when I made the starter but I pitched it after 12 hours on the stir plate which maybe wasn't enough time.

I haven't brewed with this yeast but there are some I use that take that long to show signs of fermentation. Others are pretty well done in 12 hrs depending on the temperature.

For larger than 1500 ml starters I always let them completely finish, cool them, and decant in order to not pitch that shitty starter wort into the beer. A 2 liter starter is close to 10% of your finished volume and is loaded with all kinds of stuff you don't want in your beer. The conditions of yeast propagation and beer fermentation are very different.

Your smack pack according to online calculators was only 50% viable. I think these estimates are a little harsh, But you would have needed anywhere between 200- 270 billion cells for this beer assuming it's a 5G batch. It requires 3 packs at that viability of yeast in your starter.

When you severely under pitch a beer, especially a large one, the yeast are stressed. Unfortunately the time the yeast were supposed to spend cleaning up after themselves they spent struggling to ferment sugars.

Just taking a look at that particular yeasts flavor profile it is possible that some of the solvent flavors you are tasting aren't from fusel alcohols. Some of those flavors in abundance from under Pitching can taste like fusels. However it's likely fusels. It's definitely not fussels.

I don't suspect that your fermentation temps are giving you issues since you seem to be following a regimen suggested by many Belgian brewers and one that I use exclusively. I too just tape an insulated probe to the side of the fermentor.

Hopefully your next beers turn out more favorable under better conditions.






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[I.P.EH]

Thanks for all of the pointers! I will definitely build up a bigger decanted starter next time and let it ferment all the way out before pitching it.

[oceanic_brew]

Thanks for all of the pointers! I will definitely build up a bigger decanted starter next time and let it ferment all the way out before pitching it.

And then make sure to follow Brulosophy experiments to realize that it all probably doesn't matter. Hahah


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