[ynotbrusum]

I have been routinely fermenting under pressure lately - usually around 10 psi and I brew mostly lagers.  I know people say that the warm fermentations speed up the fermentation, but over the last year or so, I have fermented my lagers cold - at or near the middle of the yeast's recommended fermentation temperature.  This has been in the 50's F.  The lagers still finish fermenting quickly (4-5 days) at the cold temperatures.  This is purely anecdotal, but I wonder if the pressure, itself, speeds the process.

I use a Tilt hydrometer to measure the progress and don't rely on it as to an absolute in terms of FG.  I am often able to rack to a serving keg at the 4-5 day mark (under CO2) and lager in the keg for a couple weeks before serving bright, clear beer.

Just wondering if anyone has similar or different experiences with cold fermenting under pressure...

[Bob357]

Pressure fermentation suppresses ester formation. This allows you to produce clean lagers at ale fermentation temperatures. The higher temperature causes the faster fermentation. I pressure ferment and see no reduction in time. The biggest benefit to me is being able to pressure transfer into kegs. This means I no longer need to lift full kegs into my keezer. It's also nice to have the beers partially carbonated in the fermenter. Gets it in the glass quicker.

[HopDen]

Currently fermenting a lager with 34/70 under pressure @ 50* & 10psi. First time using the Spike All in One PRV. I am hesitant to ferment at higher temps, at least for the first time using. Fermentation timeline has been nearly the same.

[BrewBama]

For a data point: I routinely ferment 34/70 at 55°F without pressure. The fermentation is within 1-2% complete in 4-5 days for an “avg strength” beer. At that point I closed xfer to a keg with a spunding valve set to ~2 bar for 7 days to secondary at 60°F before I move it to cold crash/condition/further carbonate/mature at 32-35°F under serving pressure for at least 7 days (it stays there until I need the keg).

If pressurized primary fermentation is faster than that, it could be the pressure providing the decreased timeline.


*Disclaimer*: Any comment I add is simply the way I brew beer. I am not paid or sponsored by anyone. There are certainly other ways that can be equally effective which other brewers may contribute. This is what I’ve found that works for me using my equipment and processes so I offer this for your consideration. YMMV

[M-O-O-N That spells beer!]

The biggest benefit to me is being able to pressure transfer into kegs. This means I no longer need to lift full kegs into my keezer.

I'm intrigued.
When you pressure transfer to kegs, isn't the beer carbonated from the pressure fermentation? How does one go about transferring to a keg without the foam/head being an issue?

[Bob357]

I'm intrigued.
When you pressure transfer to kegs, isn't the beer carbonated from the pressure fermentation? How does one go about transferring to a keg without the foam/head being an issue?
[/quote]

Final pressure and temperature in the fermenter will determine the carbonation level. I generally set my spunding valve to 15 psi for ale ferments and the pressure is ~half that after lowering to 42 F for a few days to clear.

If the pressures are within a few psi and both the fermenter and keg are cold when you begin to transfer, foaming isn't an issue. After pressurizing both to serving pressure, I run a jumper from beer out on the fermenter to beer out on the keg and a picnic tap on the gas in post of the keg. Gradually bleeding off pressure with the picnic tap allows you to transfer without foaming issues.

[erockrph]

The biggest benefit to me is being able to pressure transfer into kegs. This means I no longer need to lift full kegs into my keezer.

I'm intrigued.
When you pressure transfer to kegs, isn't the beer carbonated from the pressure fermentation? How does one go about transferring to a keg without the foam/head being an issue?

You pressurize the receiving keg a few PSI lower than the fermenter. I fill the serving keg with Star San, then push it out with CO2. When I transfer it looks like this:

CO2 tank > Gas post on Fermentation Keg > Liquid post of fermenter (with floating dip tube) > transfer tubing > Liquid post of Serving Keg > Gas Post of serving keg > adjustable PRV valve

I adjust the PRV so that I end up hearing a faint hiss as the beer flows in and pushes out the CO2. Fill takes a while, but you end up with a keg of carbonated beer with little (if any) foaming

I pressure ferment my lagers for convenience primarily. I'm lazy, so this lets me ferment the majority of my lagers and ales in the same fermenter at the same temp and for the same duration. The only difference is that for lagers I set my PRV for 15 PSI and for ales I set it low(around 2 PSI), just to act as an airlock. I haven't noticed a difference in fermentation speed, but I don't generally bother with gravity readings to test this out. I typically let an average gravity beer in the fermenter for 10-14 days before transferring.

[Bob357]

I'm intrigued.
When you pressure transfer to kegs, isn't the beer carbonated from the pressure fermentation? How does one go about transferring to a keg without the foam/head being an issue?

Final pressure and temperature in the fermenter will determine the carbonation level. I generally set my spunding valve to 15 psi for ale ferments and the pressure is ~half that after lowering to 42 F for a few days to clear.

If the pressures are within a few psi and both the fermenter and keg are cold when you begin to transfer, foaming isn't an issue. After pressurizing both to serving pressure, I run a jumper from beer out on the fermenter to beer out on the keg and a picnic tap on the gas in post of the keg. Gradually bleeding off pressure with the picnic tap allows you to transfer without foaming issues.
[/quote]

Forgot to include connecting CO2 to gas post of fermenter when transferring.

[ynotbrusum]

For the receiving keg, I go in through the out post and set a spunding valve with a "keg stopper" on the gas in side, to allow for setting a small differential between the CO2 pressure on the fermenter and the CO2 pressure on the receiving keg - that pushes the beer out at a nice slow, foam-free rate.  I use bottled CO2 to push from the fermenter (just to keep it at 10-12 psi during the process).

I am willing to admit that I don't know why the fermentation is completing more quickly than a non-pressurized fermentation, but it seems to be the case.  Maybe a side by side experiment is in order to eliminate doubt - if I can keep the variables down to just pressure versus air lock fermentations. 

Keg stopper:  https://www.morebeer.com/products/duotight-flow-stopper-automatic-keg-filler.html?gclid=CjwKCAiAy_CcBhBeEiwAcoMRHHc7Qlvl5mUYuaVzP3RpqO3pDhONQDZtQhFm7sxOblvIgEONdZSEVxoCzYkQAvD_BwE

[Akshay Thakur]

Pressure fermentation or possibly higher defined as fermenting or brewing below stress is a idea that has been gaining in reputation withinside the homebrewing network over the previous few years.  Craft breweries have used this method for lots years, and now because of the innovation and development of brewing device homebrewers are capable of use it and obtain surprising results.