Intentionally stressing the yeast - looking for advice

[Golyo]

I am looking for experienced brewers, who can tell how they intentionally stressed yeast when going for specific flavours (e.g. for Saisons, Farmhouse ales).
I've read some people here using 20% less yeast and saying it is for stressing the yeast, but pure logic contradicts that 20% can mean much flavourwise. Yeasties reproduce exponentially every 90 minutes or so, 20% seems nothing to me and Brulosophy guy also has some experiments showing that it shouldn't be enough to be perceivable. When you wanted to stress the yeast, what did you do?

I am just getting into saisons, 5th batch tomorrow, 2 different strains (3711, 3726). What would be your 3rd and 4th?

 

[Denny]

And then there's what Dr. Clayton Cone of Lallemand had to say....that pitching more yeast, not less, will give you those flavors. It's because the same enzyme, acetyl coA, is responsible for both cell growth and ester production. When it does one, it doesn't do the other. So, when you "underpitch" the enzyme goes to cell growth and you get ewer esters.

 

[GPP33]

Following....I've got a Saison recipe that I really enjoy but is a little too clean. I don't necessary want to change the flavor, just amp it up a little.

 

[Smellyglove]

And then there's what Dr. Clayton Cone of Lallemand had to say....that pitching more yeast, not less, will give you those flavors. It's because the same enzyme, acetyl coA, is responsible for both cell growth and ester production. When it does one, it doesn't do the other. So, when you "underpitch" the enzyme goes to cell growth and you get ewer esters.

As far as I understood synthesizing of esters there is a group of enzymes called alcohol acetate transferase(es) (AAT) which is a great contributor to creating esters with beer. The more cell growth the more AAT will be in the beer, thus creating more esters.

 

[Denny]

As far as I understood synthesizing of esters there is a group of enzymes called alcohol acetate transferase(es) (AAT) which is a great contributor to creating esters with beer. The more cell growth the more AAT will be in the beer, thus creating more esters.

I'll have to look into that.

 

[day_trippr]

If I were to list the anecdotal incidences of unexpected esters they'd all involve major under-pitches in "first use" recipes.
There was the Spencer "family yeast" dregs in a patersbier that turned out way bolder than anticipated, the first Conan pitch that was unbelievably peachy (and not in a good way), and my first 3787 batch that was crazy phenolic.
Every batch saw the same tight temperature control that I've used for over a decade so it wasn't yeast run amuck - quite the opposite, really. Quiet ferments that carried a hidden mallet of character

Cheers!

 

[bronzdragon]

I had never underpitched before (on purpose,) before this year. I recently brewed a light bodied Belgian style Wit and wanted some clove, banana, bubble gum type flavors to be present. I under pitched by 50% and also kept the beer much warmer than I usually do, and insulated the carboy. It was probably in the upper 70s F. It was a quick fermentation. The beer turned out clean and while it is a good tasting beer, I did not achieve the flavors I was looking for. It may have been my choice of yeast, as I used Fermentis SafeBrew S-33. I will use a different yeast next time.

 

[AZCoolerBrewer]

The only time I have under pitched was when a made a steam beer using WL San Francisco lager. The pack was expired and didn’t take off for 48 hours. I designed the recipe to be close to anchor steam and fermented at nominal steam beer temps. I did not get the steam beer flavor I was looking for. The beer was ok but didn’t have that steam beer quality. So at least for that, I’m not sure that flavors got amped up for stressed yeast. I would say rather that my steam beer in that case was cleaner if anything more like a standard lager.