High pressure lager yeast at room temps

[Bosco]

Hello everyone,
I'm an all grain homebrewer of several years. I've tried searching online and asking on homebrew forums about Brewsters Yeast L36 high pressure lager yeast and fermentation under pressure at higher temps, but have found nothing.

Description:
L36 High-pressure Lager average apparent attenuation • medium flocculation • broad fermentation range Produces an authentic-tasting, mature lager beer in about a week! Ferments at room temperature under 15psi until final gravity is reached. Conditioned at near-freezing temperatures under 15psi for a few more days. Should not be repitched, but rather propagated fresh every time.

My curiosity was peaked enough that I got a large corney keg and fitted it with an adjustable relief valve and gauge to maintain 15psi. I have a starter of L36 going and I'm brewing an American style lager Friday. I was surprised homebrewers aren't showing any interest and the only mention I could find of this process, was from professional brewers, so here I am.
I have read Noonan's "New brewing lager beer" and as technical as it is, it doesn't mention fermentation under pressure. I would like to know the details of what's happening during fermentation under these conditions. Any info/opinions/experiences would be greatly appreciated.
Thank you for your time.

[lhall]

Bosco,

I would be careful with your pressure relief system, any blow-off trub in the pressure relief valve and you just made a nice bomb.

I believe Miller has a patent on this high-pressure lager system, I remember reading the patent in detail online somewhere, but I can't find the link now.

There was also a story of an experiment a professional brewer did of this type, it was in the New Brewer magazine a year or so ago. I believe their results showed a higher level of diacetyl than acceptable. You also cannot repitch the yeast due to the stress on the yeast when harvesting at this pressure.

[Jephro]

This discussion got me thinking about the effects of pressure on yeast. I try get to as much natural carbonation in the beer as possible. We use a Barby Kuhner towards the end of fermentation to regulate blowoff and build head pressure, but how much is too much.
What pressures are acceptable before you start damaging your yeast, or end up with a stuck fermantation?

[beauxman]

For some reason (maybe residual brewers school memories) I am thinking 30PSI (on the yeast, not gauge) is the limit. I too am leary of pressure on tanks and yeast health but also realize that most of the studies were done by large brewers with 1000 BBL tanks or more that would have had supreme pressures on the yeast due to the hydrostatic pressure + trapped CO2 pressure (Gauge). I would imagine that in our world of 5-10-20 BBL systems, it never really becomes an issue, but I am not sure and would love to hear other opinions-facts! If you are playing by the rules and don't take your non ASME rated tanks over 14.5 PSI, then I would bet you are safe. The other factor is you will change your yeast behaviour and by products of fermentation, and I don't recall the specifics....but it will change your flavor profile...again, someone else can chime in here. I think one of the benefits is a quicker fermentation cycle, but it is always a trade off that as a homebrewer I don't think is needed. But as a home brewer, what do you really gain by short-cutting the cycle? I would think that the wait is half the fun! Use a traditional yeast and fermentation profile, and as Charlie says..."relax, have a homebrew!" It is not a race...(unless you are pro and have to clear the fermentation vessel by next week to make the next seasonal!)
-Beaux

[Beersmith]

I believe the article that Linus was referring to was an article by John Harris of Full Sail. If I recall correctly, he experimented with fermenting under pressure in order to increase the tank fermentation capacity (no loss due to blow off).

As far as our experience goes, we do not ferment under pressure, rather (like Jephro) we bung off our fermenters near the end of fermentation (based on SG) to retain as much natural carbonation as possible. We normally generate approximately 10 PSI in the fermenter by the time fermentation is complete. In order to avoid diacetyl issues, we use a 1-2 day rest (at 68F) depending upon the beer style. We have had no issues repitching yeast under this scenario.

[kuhnhenn]

Bosco,

I was excited to here that White Labs also offers a HP yeast. A buddy of mine in germany was running a production brewery with HP yeast to brew clean lagers in 5-6 days. But when I asked Chris WHite about the yeast he said that yes you can produce clean non diacetyl beers very quickly, but that it lacks the flavor's that you want out of a traditionally brewerd lager. He said that you are better off taking the time with a good Lager yeast to get the good depth of flavor profiles. (I have a pressure vessel rated at 4BAR that I wanted to make use of). So I gave up on my experiment with high pressure yeast. But I am not sure if there are other pressure yeast's out there with more flavor or if it is just the high pressure and temp that make it lack the flavor. Please post what your experiment concludes.

Cheers,

Eric Kuhnhenn
Kuhnhenn Brewing Co.

[Bham Brewer]

I know this thread is OLD but I just saw it! LOL

About 7 years ago I worked for a pub chain in the south east, I was the unofficial 'corporate' brewer and ran my brewery and oversaw the brewers at 2 other locations. We all used the Barby Kuhners to great success.

I would cap my tanks 24hrs after knockout when I saw strong, active ferment. Pressurize the tank (ASME certified of course!) to 1.4 bars (arox 20-20.5psi) on the Barby Kuhner and go... The Barby Kuhner did a great job of keeping the pressure stable at 1.4 bars and the beer was 100% naturally carbonated.

I brewed both Ales and Lagers with the system and was very, very happy with the outcome of both. Turn around time on my ales was aprox 8-10 days brew to glass and about 30-45 on lagers... I would always plan the extra aging time on lagers, though I could have sent them to brite tanks as early as 18 days in most cases.

I never had any issues with repitching the yeast and would usually go to about the 6th generation on ale yeast. With lagers only the 2nd or 3rd gen, since I didn't keep lagers in standard rotation. My house yeasts were Safale S04 and Saflager S23. I would do my ale fermentations at 70 degrees, holding that temp for aprox 5 days before crash cooling to 32. My lagers would start at 70 then step down to as low as 38 over the first week to 10 days or so depending on starting grav. and fermentation progress. When under these conditions the saflager S23 made a very, very nice Czech pilsener.. very clean, crisp with a nice malty palette. Other lagers I brewed this way included a doppelbock, schwazbier and maerzen/fest biers.

I think that, as with so many other things, you would need to experiment with different yeast strains in your brewery environment... there are so many variables that it is impossible to say that what worked for me would work the same for you.