Pressure fermenting lager experiment

[McMullan]

After 5 days at 11-12℃ I wasn't too impressed with how fermentation was going. Way too slow. I'm using WLP800 to ferment a Czech Pilsner with loads of Saaz. So decided to experiment with it, to add a little excitement Now fermenting at a noticeably higher rate at 18℃ under about 15psi.

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From right to left: FV connected via gas 'out' to sanitised keg via liquid 'in'. The liquid 'in' on the keg has a silicone tube going to the bottom of the keg. (I'll add a keg float after the lager has been transferred.) I've added a Blowtie spunding on the gas 'out' of the keg so that CO2 from the fermentation purges air from the keg and brings it up to equal pressure (as the FV) so transfer just involves simply hooking up a liquid line (a 'jumper') then releasing some pressure from the pressurised keg. I was even entertaining the idea of collecting another keg's worth of CO2, to complete the transfer or even for serving, as I've got some empty kegs at the moment

[Cobnut]

Be brave, wind the temperature up a bit more...you can do that quite happily under 1 bar.

My standard lager brew is (all at c.15psi):
1 day @ 18C
1 day @ 20C
1 day @ 22C
2 days @ 24C
then cold crash for a couple of weeks.

Current brew using this method hit FG after less than 3 days. So I probably could've gone straight to cold crash after the 22C stage....perhaps I'll tryb that next time? Lager fermented in 2-3 days...but then worthwhile to cold crash and lager!

[McMullan]

Which yeast(s) are you using? With WLP833 and WLP940 I get fermentations complete within about a week at low temperatures, 10-12℃. I seal the FV after about 5 days. With WLP800 is was a completely different story, attenuation was about 35% after 5 days. Unless this beer turns out very nice I won't be using WLP800 again. Apparently it's a cold adapted ale yeast rather than a true lager yeast, so likely it performs better at higher temperature. I'll consider ramping it up to 20℃. I'll be aiming to increase the pressure to about 30psi towards the end to get it highly carbonated before lagering at 0 for a week or three.

[MashBag]

Never tried pressure fermentation, what are the benefits?

[McMullan]

Never tried pressure fermentation, what are the benefits?

The only benefit (especially for my under performing lager fermentation) is speeding up a slow process by allowing higher fermentation temperature without producing off flavors. I’m not convinced it produces better beer. My best lagers so far have been fermented the traditional way.

[MashBag]

Thanks. That makes sense.

[Cobnut]

I’ve used MJ bohemian lager yeast (dry), but also wyeast 2124.

The former I think gives slightly better results under these conditions, but of course, loads of other factors at play here, so hardly a scientific study!

I find this method works quite well for me.

[McMullan]

Well that's definitely pushed things down the right pathway. Attenuation now at about 55%. A big change in the rate of fermentation. Doesn't taste terrible at this stage either. Boring, but not terrible. I hope the Saaz come through later. Checked my notes and attenuation was only about 32% after 7 days, not 5. That's pretty slow in my limited experience of fermenting lagers. Anyway, I think I'll increase the temperature to 20℃, just so I can 'get the t-shirt'

[McMullan]

I’ve used MJ bohemian lager yeast (dry), but also wyeast 2124.

The former I think gives slightly better results under these conditions, but of course, loads of other factors at play here, so hardly a scientific study!

I find this method works quite well for me.

That makes sense. Yeast that survive the commercial drying process are likely to be more stress tolerant therefore cope better with these stressful conditions under pressure. Not sure I'd opt for dry yeast personally, though. And to be fair I have had very good results using WLP833 and WLP940 under pressure. Yeast are generally very hardy so should be fine under 15psi. I think I've got enough volume to transfer a few litres into a mini keg before increasing the pressure to 30psi, which should make an interesting comparison if it ruins the beer.

[McMullan]

Transfer to keg was very straightforward. Just changed one disconnect, connected to the liquid-out post and purged CO2 from the keg occasionally. So simple I was convinced I'd forgot something.

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Beer was fizzy and bright after cold crashing when FG reached.

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The wife (who prefers lager) thought it was nice. It's not bad, but I'm hoping it gets better after some weeks lagering in my unfinished keezer.

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[McMullan]

The observant among yous might have noticed the glass used to sample my experimental lager boasts the CAMRA logo. Purely random and mainly because I most likely stumbled home one night from a beer festival, clutching a pint in my hand. Like a lager lout! There was no premeditated dishonesty on my behalf. Honest. Anyway, it got me thinking about how CAMRA might view my lager. It’s a live, naturally conditioned beer fermented with real yeast, right? So I thought I’d look up CAMRA’s website for any views expressed about lager. I was half expecting to be brutally accused of storing kegs of ‘piss’ in my basement, but I didn’t find any views expressed about lager at all. I found this elsewhere, though.

[Jer]

Hi McMullan
What scales are you using to gauge the corny weight during transfer? I like your set up

[john luc]

I like the fermenter. I am having 2 30 liter kegs built like this atm. having 2 50mm ferrules added to the side to be able to fit a thermowell and a sampling tap too. When fermenting will the gas coming off the fermenter fully fill the corney keg.

[McMullan]

I like the fermenter. I am having 2 30 liter kegs built like this atm. having 2 50mm ferrules added to the side to be able to fit a thermowell and a sampling tap too. When fermenting will the gas coming off the fermenter fully fill the corney keg.

Yes, no problem. I reckon you could fill several kegs.

[McMullan]

Hi McMullan
What scales are you using to gauge the corny weight during transfer? I like your set up

Very cheap and cheerful. Got mine a couple years ago for about 17 quid. Not a precision instrument, of course, but good enough to measure 20kg beer.