Calling those fermenting under pressure!

[The Baron]

Well here goes lets pull the pin out on this one. I believe that fermenting under pressure has its purposes, it does speed up fermentation and can eliminate oxygen but I am a believer that apart from say NEIPA's maybe most beers should not have any problems with oxidisation if you have good brewing practices.
I think it is the latest panacea that the brewing equipment sellers/manufacturers are ramming down are throats to sell expensive toys to us homebrewers until they find the next idea to come along. Now I have said it does have its good points but it is taking away from good brewing practice and I will repeat most oxidisation is from bad brewing practice and we are creating brewers that may never have the skill to create a good beer without the latest tech.
There is no replacement for experienced brewing practices
Well that's my thoughts Ps I have never had a oxidised beer in years of brewing

 

[Brew_DD2]

Agreed. I brew a lot of NEIPAs and I don't bother with pressure fermenting. Closed transfer to keg is all you need to avoid oxidation. If I want to ferment quickly I just use Kveik.

 

[krispn]

I don’t think anyone is claiming it’s necessary or better but just another facet of the hobby to try if so inclined. If the most someone gets out of playing with a pressurised set up is non-oxidised NEIPA and hazy pale ales and that was their goal then that’s something. It’s likely the “haze craze” which has seen home brewers take more of an interest in utilising pressure and I suppose manufacturers are satisfying that demand.
A while back it was stainless steel this and stainless steel that so folks could feel their home set up was more ‘pro’ or simply more durable, whatever their reasons I don’t believe anyone would claim that a good old plastic bucket in a fridge (or some temp control) can’t make decent beer. Trends come and go and folks will gravitate to new stuff to keep the hobby interesting for them or to simply have the latest gear. As has already been said but is worth repeating... At the heart of any good beer is good brewing practices.

 

[Wynne]

Just a short note on CO2 stress and mutation - high pressure slows down cell division and overall cell mass, reducing the number of generations in the wort and the cells may eventually after multiple generations adapt to the CO2. Stresses to the cells in this regard don't actually cause mutations, rather it provides a selection pressure for genetic drift towards CO2 tolerant types. Sorry to be a pedant but stresses don't cause mutations in yeast, and will only select out mutations if they are caused as a steady state. The viability of yeast under CO2 pressure was questioned in anecdotal reports in 1983 but subsequent studies on yeast response to stresses hasn't shown this to be the case.

Paper of interest if anyone keen to read about this:
Richard, Lannig, Guillouet, Stéphane E & Uribelarrea, Jean-Louis, 2014. Quantification of the transient and long-term response of Saccharomyces cerevisiae to carbon dioxide stresses of various intensities. Process biochemistry (1991), 49(11), pp.1808–1818.

Consequently, yeast cells grown in presence of CO2 enrichment showed a different short-term response to a CO2 step-increase of same intensity than yeast cells grown without CO2 enrichment. The response to the second CO2 shift-up was much lower than the response to the first step-increase pointing out that yeast cells may have acquired a resistance to CO2 stress during the A-SS2. This increase of the resistance to a CO2 stress may be similar to the increased resistance of yeast cells to H2O2 observed during four to five generation after exposure to an initial 0.7 M NaCl stress [60]. However in the present case the long-term effect was observed after stabilization of a new steady-state.​

Thank you @DocAnna, the paper you reference is interesting (if a little beyond my knowledge of biochemistry). From my understanding, the experiment was conducted under respiratory rather than fermentative conditions and didn’t use wort as a medium. It would be interesting to confirm whether yeast under brewing conditions respond similarly to increases in CO2 pressure and whether serial re-pitching of yeast would give rise to a CO2 pressure tolerant strain, as you logically suggest.

 

[krispn]

So my pressure pale ale turned out just as I’d hoped (and hopped)!
Hazy ‘bright’ and a lovely aroma with a nice bitterness. Not to dry but enough bitterness too know you’re drinking a beer not a fruit juice.

 

[SteveB.]

Just an update on the Keg King PRV's from Brew2Bottle.
I just received a Blue 10psi PRV and a 15psi PRV from them to see if they could replace the PRV fitted to the Corny kegs lid.
And indeed they do as they are exactly the same size with the same thread. They screw straight into the lid of the Corny so could be used instead of a spunding valve at a fixed pressure (10 or 15psi) when fermenting under pressure. Must test them soon as my first venture into fermenting under pressure in a corny.
On a different subject, though relevant, I use an iSpindel to monitor the fermentation progress and unexpectedly it works inside the corny OK.
I was wondering though would the iSpindel be OK operating at 10-15psi?

 

[krispn]

You’ll likely have to adjust for the pressure but if you’re starting gravity is say 1.050 and you pressurised the corny you could maybe work out the difference the pressure adds?

 

[cheeseyfeet]

On the keg king PRVs I recently bought both the 10 and 15 PSI ones from B2B.

I tried the 15 in a brew and had to abandon it and go back to my spunding valve, it was releasing pressure much lower than 15 PSI, constantly letting out. My gauge showed 0 PSI after 2 days fermentation so definitely off.

As soon as I went back to the blowtie the pressure crept up.

I'm using a KL all rounder but this shouldn't matter as the threads are standard.

I have contacted B2B and am waiting on a reply.

 

[Brew_DD2]

I've just ordered a 10psi to try.

 

[krispn]

7 day lager. Not 100% correct. Smells right, wee touch of sulphur, some odd mid palate thing going on, ends ok with some malt flavour . It’s as if Zack Synder did an edit of my last Helles.

I used the Mangrove Jack M84 so not sure if the yeast is doing something here? Certainly worth another go with a different yeast!

I should add whatever I'm tasting may age out so I'll keep this one cool and leave it a few weeks and see what happens.

 

[muppix]

I was wondering though would the iSpindel be OK operating at 10-15psi?

I'm using a Tilt Pro and tested it to 15 PSI for 24 hours prior to dropping it into an actual brew, no issues. I don't see why an iSpindel should be any different, but it's an easy thing to test without jeopardising an actual brew ...

 

[RoomWithABrew]

Just brewed my first NEIPA and the Ispindel sank on day three when I allowed a bit of pressure to build up. It had been working fine.
Fished it out and this is what it looked like.


Opened it up and smell of acetone really from the liquid.

Had no hopes for it at all and expected to just salvage the bottle and sled.

Took it all out and gave the electronics a good scrub over with isopropyl alcohol and left it to dry in a draught and the sunshine.

Then into a bag with silica gel dessicant further 48 hours.

Yesterday plugged it in to charge, bit stiff getting the usb plug in but it got there.
Expected fireworks when I powered up the charger or nothing and amazed the red light went on.
After a few hours charging thought to myself better test it works as light was blue.

Can't believe it worked straightaway.

Just need to reassemble and calibrate again.

I'm flabbergasted. It was in fermenter for ten days submerged and the beer tastes great as well.


Plenty of other pressure ferments have been fine though, wonder whether the 35 celsius kveik ferment made everything a bit softer and leaky.
Have ordered some orings to fit the top so we'll see how long they take to get here from China.

 

[muppix]

I'm flabbergasted. It was in fermenter for ten days submerged and the beer tastes great as well

Personally I would think twice about drinking that, just because you can't be sure what's leaked out of the battery.

 

[nixhaz]

Just a note on this, the spunding valves from Kegland are super cheap on the AliExpress site (through the Kegland official shop). Arrive in less than 2 weeks in my experience.
I've used my Ispindel in 2 brews so far at 13PSI and it has been fine. I do notice a slight uptick in the reading once the pressure is applied (like 2 gravity points).

 

[phildo79]

I have only used my iSpindel once and something very odd happened. Fermentation was over, according to the reading. The blow-off tube was idle too. I dropped in the dry hops and pressurised the keg to vent any oxygen that might have got in whilst dry hopping. The iSpindle started telling me that the gravity was dropping again. I put this down to the keg now being under pressure but when I transferred to the serving keg, it was carbonated. Pretty perfectly carbonated, actually. I can't imaging the pressure used to seat the lid and vent the keg did this. My only other thought is hop creep.

The FG was calculated to be 1.013 but the iSpindel said it was 1.008 before dry hopping. But after dry hopping it went down to 1.002 and became carbonated. The beer was supposed to be 5.4% ABV but if the readings are correct, it's 6.8% ABV. Must say, it doesn't really taste like an almost 7% beer. Has anybody else experienced something similar?

 

[RoomWithABrew]

Definitely wouldn't rely on the gravity reading of the ispindel once krausen sits on the lid or pressure comes into play. Only takes a tiny change in volume and the ispindel reads differently. But it really reliable on temp and it shows a trend really well.
I might have tracked down a rigid clear tube that is waterproof that will work instead of the petling, if so it will be a game changer with the pad charger I won't need to open the ispindel and it will be much cleaner. Will keep you informed.
I would only trust a hydrometer reading.
I do always aim to have my beer carbonated by the end of fermentation and to have flushed out and purged at least one keg.
With kveik that often means ferment pressure up around 30 psi. I fill the keg to that pressure as well. Then when pressure drops during cold crash and I do the closed transfer the excess gas in keg I'm filling pretty much runs the transfer.

 

[muppix]

Definitely wouldn't rely on the gravity reading of the ispindel once krausen sits on the lid or pressure comes into play

I've a Tilt Pro and it's a similar story; don't pay attention to absolute values but the progress curve is worth its weight in gold.

 

[krispn]

Just a follow up again...

Brewed my Imp stout a fews weeks ago with Mangrove Jack M42 at 25c at about 12psi which has come out tasting good. See the picture below... I didn't quite get the efficiency I was after but that could well be down to other factors in what was a 1.090 SG beer (three packs of M42 used in this one, maybe could have used four?) I've got favourable feedback from some mates who have tried my beer before and who are into their stouts so i can see no reason not to use the pressure FV in future brews of this one as the quicker turnaround is a bonus.

I have also made an Altbier recipe on Monday with Imperial 'Kaiser' yeast. I have brewed this beer on a couple of occasions in a non-pressure FV so have a good idea of how it should taste. I prefer 'Kaiser' yeast for this brew over the 'Dusseldorf Alt' and 'German Ale' yeast I've used in the previous brews of this one.

*Edit*
This was brewed at 18c for the first 36 hrs then increased to 25c in and about 12psi and has finished in and about the expected FG (I may be getting a slightly inaccurate reading on my hydrometer, I'm only a point or two off, but this could be a combination of temp/carbonation). I'll be doing a final gravity check tomorrow before the cold crash. The hydrometer sample was tasting promising and I didn't notice and off flavour or unexpected characteristics coming of this one. By all accounts another positive fermentation under pressure.

 

[RoomWithABrew]

@krispn
Is 18c a warm ferment for kaiser or its normal range? I find that I can ferment warmer under pressure without the non pressure ferment too warm side effects.

 

[user 18729]

Agreed. I brew a lot of NEIPAs and I don't bother with pressure fermenting. Closed transfer to keg is all you need to avoid oxidation. If I want to ferment quickly I just use Kveik.

Exactly this