High pressure ferment

[MrFancyPlants]

Does anyone ever ferment at really high pressures? I did a recent faktoberfest batch at about 40 psi, and it turned out ok.. I think my hopping and recipe needed some tweaks, but the kveik yeast turned out lagerish with some drastic temperature fluctuations.
I know there is no real reason to go above 40 psi, since that works out to pretty good natural carb rate when brought down to serving temperature. But I’m going on a trip for a few weeks and though I would let my 15 gallon torpedo keg ramp up the pressure some while I was gone, to see what happens. Steam beer, right?

 

[CornKing]

I've never heard of anybody fermenting that high. I think you're on the bleeding edge here. Thanks for sharing the data point!

 

[MrFancyPlants]

The fäktoberfest scored some flawless reviews from some biased buddies. They didn’t pick up the same unbalanced bitterness than I did. It is clearing up more and more at kegerator temperatures. A bit of chill haze seems to be dropping out slowly. Maybe I should have boiled longer. They deemed it crushable.

 

[MrFancyPlants]

My non-professional non-scientific hypothesis is that higher pressure acts like temperature control. It slows it down and suppresses esters, even more so than at 10-15 psi.
Yeast seem to be pretty well attuned to fermenting under pressure, they certainly have had some practice in their domesticated history. I don’t think they register much of a difference between 10 or 100 psi, but not much reason to go over 40 in my book since that works out to decent carbonation level in my book.
What are the emergency blowoffs set to for your standard corny? Could I use that as a spunding valve for a high pressure test batch? Or am I going to plaster the ceiling with beer when it starts to release?
Maybe I set a small batch outside in the summer heat and see what turns out?
Edit: I see it is dangerous to use PRV as spunding, likely due to the lack of redundancy. But I could also set my spunding high to the same effect. I’ll play it save but maybe try targeting 60 psi for my next batch.

 

[DuncB]

I ferment lagers around 30 psi towards the end, start at 0 psi and build to the high pressure. I'm using conical pet fermenter which says no higher than 35psi, you certainly see ferment occurring at the higher pressures. Gas production confirms it as well.
My lagers all been well received using opshaug kveik about 30 Celsius.

 

[CornKing]

Yeah the limiting factor I see, if it isn't the yeast, is the vessel. My all-rounder is rated up to I think 35 PSI. A corny is rated to usually around 50 I think? I wonder how many yeasts are capable of handling these pressures. I have read of folks using many common ale yeasts to 10-15 and 34/70 can certainly do the same, although I have read that some lager strains (like I think wlp820 and wlp833? I've just come across anecdotes) struggle with pressures. Then there are the types of yeast in which the unique fermentation profile is desirable and ester suppression isn't desirable. I'm thinking here of saisons, which tend to be sensitive to pressure, and British ale/NEIPA type beers. You might not need to pressure ferment for temp control, but spunding to save time and CO2 could backfire if you miss those yeast derived esters.

 

[DuncB]

If I want the yeast character I don't pressure ferment and only " turn it on at the end". Most expression occurs in the first few days.
I want some pressure and a sealed system for neipa at the dry hop stage.
Pressing ferment is not a panacea but an option.

There is a keg king video where they ferment to their vessel failing. Turbo yeast was still going at 100 psi.

 

[DuncB]

Here it is

Seems ideal for real ale that that I serve with the beer engine and just needs enough CO2 to replace the volume loss from the keg and a few psi.
Regarding the ability of yeast to ferment under pressure this video gives a few clues.

Given the pressure rating of a corny keg the 35psi seems well in the safety range.

 

[MrFancyPlants]

I have inadvertently tested the high pressure ferment capabilities of kveik. I didn’t test my spunding valve out to realize it was clogged and was using a yeast cake from my last batch. The Kveik kept the batch warm and fully fermented in less than 24 hours despite getting up to the pressure required to push through the emergency prv on my 15 gallon torpedo keg. I am really fortunate that it didn’t clog too as it misted my wall with some of the 1lb of Hallerrau dry hop stand. No damage and not too big of a mess to clean up, very lucky. It was less than half a pint of perceptible beer loss in the blow out.

Now the question is how did the beer turn out. Any semblance of pseudo lager? Or, will it taste like marmalade? Stay tuned to next weeks tasting, though my last batch really took over a month to clear and hit it’s prime.

 

[MrFancyPlants]

I have inadvertently tested the high pressure ferment capabilities of kveik. I didn’t test my spunding valve out to realize it was clogged and was using a yeast cake from my last batch. The Kveik kept the batch warm and fully fermented in less than 24 hours despite getting up to the pressure required to push through the emergency prv on my 15 gallon torpedo keg. I am really fortunate that it didn’t clog too as it misted my wall with some of the 1lb of Hallerrau dry hop stand. No damage and not too big of a mess to clean up, very lucky. It was less than half a pint of perceptible beer loss in the blow out.

Now the question is how did the beer turn out. Any semblance of pseudo lager? Or, will it taste like marmalade? Stay tuned to next weeks tasting, though my last batch really took over a month to clear and hit it’s prime.

FYI: turned out more like a pseudo lager than a kveik. I think pitching on the cake plus pressure kept the esters to imperceptible levels.

It’s time for me to clear out the trub and excess yeast in my torpedo and start a fresh batch. I was thinking of drying the oak staves in an off/slightly open oven, to try and resuscitate the kveik character with an under pitch?

 

[odie]

I think 40 psi is fine for a lager. The psi needed to stop or kill yeast is in the thousands, not hundreds or tens...

Lagers do not need "yeast expression" IMO.

But at 40 psi, yeast propagation/colony growth is probably hindered somewhat. How much I don't know.

I like to start my lagers around 10ish. I use the blue PRV valves which are nominally 10 PSI-ish.

After a few days I'll swap to the red PRV which is around 35psi and let it go from there. at the temps I'm fermenting at, it's a pretty good ballpark for carbonation for most all my beers.

 

[HM-2]

40 PSI is pointlessly high, IMO. You get all the benefits of pressure fermenting between 5-10, and most yeast vendors suggest 1.0 Bar as a maximum pressure.

 

[odie]

this reminds me...I need to swap out the blue PRV for red on my winter lager. But it might be finished already anyway

 

[Beerstein]

I did a kveik at 30psi once, but only by accident. Didn't seem to have any affect on the taste.