Pressure Fermentation Temperatures

Yeast & Fermentation
1

Hi folks,
I want to try to pressure ferment a German Alt using K-97 yeast. I figure, since it’s an ale, I should set my spunding valve @ around 10PSI but what temperature should I keep the fermentation at? I keep hearing “room temperature” but here in SoCal that’s like 80. I know the temps can be higher for pressurized and I do want a fast ferment, but how high can I get away with? My biggest issue is that I don’t have a basement and my fermentation cooler doubles as a kegerator and has a keg in it now. Can I leave the fermentor out at room temperature (~80 here) and not have issues with off flavors?

2

80 is high. I ferment under pressure for all my lagers at regular fermentation temps. Where you save time is getting it carbonated since it is carbonated when fermentation is over. That said you can speed it up if you have temperature control. Pitch the yeast warm to jump start the fermentation then drop the temp to finish. An Alt should be lagered though. Might be able to do a pale ale though

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3

I would try the pseudo lager Kviek strains of yeast like Oslo and Lutra. They are really impressively clean at high temperatures.

4

Thanks Squeegeethree and Brew_cat! I have been using Voss and Opshaug for fast ferments, but I wanted to try to get back to traditional yeast strains in some yeast forward beers, but still be able to ferment quickly. I think I may try to pressure ferment in the temperature controlled chamber and just go up a couple of degrees and see how that goes. I will probably have to rig a bubbler to my spunding valve so I can see how the fermentation is going.

5

Voss is good but you should try these pseudo-lager strains. IMO, with them you will get a much cleaner lager than fermenting with a lager strain at high temperatures.
Keep in mind that “traditional” is a loaded word in brewing. Lager yeasts are “new world” strains and most likely newer to European breweries than the Kviek strains are to the farming communities they were fostered in.

Edit: I reread the update genetics studies on Lars blog. A really good read. Seems Kviek, Lagers and Heffe strains all budded about the same time and might be from the same cross breed of yeast.

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6

I agree with squeegeethree initial recommendation of to try the kveik yeasts when you ferment at higher temperatures. I made a czech pilsner and fermented at 75 F not because I chose that temp as my basement was at 61.7 F. That’s how much the heat the yeast generated during fermentation! I still have kegs of both a kveik lutra yeast czech pilsner and a exact same pilsner except fermented with wyeast 2278 czech pilsner fermented at 53 F and I can not taste a difference and they both are really good.

Per their literature, you can ferment up to 95 F. Try the kveik yeasts. That is what I do when my basement warms up in summer.

If ambient is 80 F you will see peak fermentation temperature higher than that due to the heat of reaction. I would not worry about that as, and dont @ me for this, but when you ferment under pressure the reaction rate actually decreases which mean your exotherm will likely be less than what I experienced. I know this from a peer reviewed technical journal publication. As beerkat (sp?) says, the time savings in pressure fermentation is in not having to carbonate.

7

I know you’ve read thAt you can ferment under pressure at high temperature and force a quicker fermentation. Ive read about that as well. The theory being the CO2 and pressure retards the formation of esters. I’ve just never tried it. But i would still keep it at the upper end of the yeasts range.

8

Is there any positive or negative effects of fermenting a lager under pressure at normal lager fermentation temps? I just got a spunding valve for my concial and im going to brew a lager this weekend. The current temp in our shop is around 45 to 55 degrees which is where Ill have this fermenting. I could do it without pressure but was just curious if i let it build up to 10 or 15 lbs of co2, would it benefit at all?

9

the benefit I’ve found is the beer is conditioned when it’s finished and also as long as I see pressure I know there is no O2 intake. My main reason is keeping the O2 limited

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10

That makes sense. Do you still lager it for any specific time? And what about diacytel? I was thinking about kegging it and then pulling it into the warmer house for a few days before putting it into the keezer.

11

Never hurts to do a diacetyl rest. Cheap insurance. Disclaimer: never had diacetyl. But I don’t want to find out by cutting corners.

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12

I still lager it but carbonated. I do a D-rest and a cold crash and since its sealed the issue with O2 intake during temperature change is negated. I have a freezer/fermetatin chamber so its easy. I’ll put the receiving keg in there so its at the same temp. The keg is purged with excess CO2 at the same time.

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13

Oh I see your question about the d-rest is after kegging. Interesting :question:. I D-rest in a wave before fermentation is complete. So if you transfer before fermentation is complete it may work.

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14

As I understand, yeast has to be active to remove diacetyl. That process is called scavenging. So as your fermentation slows, then a warm up for the process to happen.
Sneezles61