Ferment under pressure

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Dr.Reddog's picture
Ferment under pressure

This is a copy of a post I made a few days ago on NB here, but thought I'd add it here for the experimental value. I've been fermenting under pressure with this method with great results.

Fermenting under pressure allows for faster turn around and warmer fermentation without off flavors. The fastest I've done with this method from grain to glass is 10 days for an average gravity (~1.050). There's a brewer on HBT that does lagers at room temperature very quickly. My process is:

Day 1: BIAB/No-chill in corny
Day 2: Pitch yeast, attach blowoff tube to gas qd.
Day 5: Pull the gas qd, "capping the fermentor"
Day 10: Fermentation complete, and fully carbed, ready to transfer to serving corny

It definitely helps clarity to cold crash for a day and close transfer to the serving keg on day 11-12. I have also experimented with serving from the fermentor (from no-chill to serving all in the same vessel). It definitely works, but I pulled a lot of trub at first, and then a few oz on the first glass for about 3 days, so unless you don't mind dumping the first little bit it's worth it to transfer.

With the above method I've been running my entire homebrew operation with 3 corny kegs. I'm the only drinker in the home, so I only have two kegs on tap. I have a 3rd keg that's my fermentor that I try to keep full of fermenting brew. When one of my serving kegs blows, I sanitize it, and close transfer into it from my fermentor. Since my keg-emptying rate varies, sometimes my closed-pressurized fermenting brew will sit for a few weeks, but it's usually closer to the 10 day schedule outlined above.

My brews have been fully attenuated with this method. I am allowing the fermentor to get a little warmer than I usually do (ambient high 60's instead of low 60's) to allow it to ferment quicker. The pressure supposedly suppresses warm ferment off-flavors.

While I usually do this on low-to-mid gravity brews, I experimented on a 1.080 OG RyePA. It took about 4 days of cold crashing to fully clarify, so more like 14 days until I was drinking clear beer (although I was gladly drinking cloudy beer at 10 days). It fully attenuated in that time, so unless I got lucky it seems like you can pull off a quick turn around on higher gravity brews too.

cmoon's picture
I've tried this technique but

I've tried this technique but had really bad luck with it. None of my beers fully attenuated. I lost about three batches this way, and after asking for help from my brew club (The Maltose Falcons) and some local brewers, I began to suspect that I was losing my best yeast by blowing it out the blow-off tube. I think if I were to try this again I'd put no more than 4 gallons per 5 gallon corny keg, maybe even less. It was also suggested the corny kegs have a poor geometry for fermentation, and that fermenting under pressure might be killing the yeast. It's encouraging to hear that your having luck with this process.

I did IPA with English yeast

I did IPA with English yeast ,and ferment it under pressure 5 psi in carboy,I had one of the orange cups with 2 nozzles ,blocked one and to the other I attached tubing with adjustable pressure relive valve,it worked,the ester was almost none and also I observe the krausen was very small,result of the pressure I suppose,next I will be testing carboys on how much pressure they can really handle.

I've been experimenting with

I've been experimenting with the 2 liter plastic bottles with the pressure relief valve available online for 24$ per 20 caps, reusable. It's been really tasty, but I' not getting over about 3%. I'm using the loss in weight to calculate the alcohol, plus my own comparison with good local microbrewery beers and my trusty s80 breathalyzer.

2 liter plastic bottles can handle a 140psi according to mythbusters. The caps are cheap, and regulate at high champagne pressure on the first run, then drop to more beer like 15 psi value after that.

My computer room stay at about 75F. Which is within the recommended temp according to the extracts I have used.

I consistently end up with a loss of 50 grams on a 2000 gm bottle. which according to my calculation is about 2.5%.

I just started it, and haven't let any go past a week. But at that time, the fermentation appears to have stopped, and the weight loss ceases.

Any thoughts?

hey.. I know this post is

hey.. I know this post is super old, but i just came accross it. I'm looking to experiment with pressure fermenting, but for the life of me cant find a pressure relief valve that is cheap and seems reliable. you mentioned here that you can get a pack for $24. what are they called? where can i find these? thanks



I literally made this and am using it now . Works great . Couple things off Amazon and the rest at my local hardware store . Maybe $20-30 bucks worth in stuff.