Author Topic: Spunding Valves and fermenting under pressure  (Read 484 times)

Offline gmac

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Spunding Valves and fermenting under pressure
« on: June 05, 2014, 12:50:28 PM »
I have spunding valves for my brewhemoth conicals and I've used them a time or two when transferring beer under pressure to reduce O2 and also to move beer against gravity when it gets near the bottom of the conical. But, as I understand them, they have a pressure release that would allow for the beer to off-gas at a certain PSI.  I have also heard repeatedly that larger breweries can get by with fermenting warmer because beer fermented under pressure has less ester formation etc and produces a cleaner ferment. 

So, I am curious if it is possible to set this valve to maintain a certain vessel pressure that would replicate the pressures or at least some of the pressures that a large tank would exert on the beer.  I don't know what pressures the conicals are rated for, when I keg, I've been running them at or below 5 PSI so that I don't move the beer to quickly and also to avoid over pressure.

Does anyone actually know what the osmotic pressure would be on yeast in a large tank and what pressure might simulate that?

Thanks

Offline morticaixavier

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Re: Spunding Valves and fermenting under pressure
« Reply #1 on: June 05, 2014, 01:13:45 PM »
I believe the standard pressure used in pressurized fermentation is 15 PSI. You should verify your brewhemoth is up to that (I think they are).

There is a guy on here that uses one for that purpose. Can't remember who though.
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Offline kramerog

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Re: Spunding Valves and fermenting under pressure
« Reply #2 on: June 05, 2014, 01:16:43 PM »
Here is my educated guess.  In a conical that has a working depth of 20 ft, the average pressure is ~10 feet of H2O,  which corresponds to a pressure of 4.3 psig, assuming the headspace is at atmospheric pressure.
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Offline kylekohlmorgen

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Re: Spunding Valves and fermenting under pressure
« Reply #3 on: June 05, 2014, 03:08:31 PM »
Here is my educated guess.  In a conical that has a working depth of 20 ft, the average pressure is ~10 feet of H2O,  which corresponds to a pressure of 4.3 psig, assuming the headspace is at atmospheric pressure.

Good thinkin'. Blichmann states a max. operating pressure of 3 psi (6 ft lift from racking arm).

Homebrew conicals are designed to work under just enough pressure to transfer. They are not designed for carbonating or pressure fermentations.

Even if you set it below the max operating pressure, a spunding valve could easily clog with krausen. For units without a true relief valve (Brewhemoth), no relief + pressure = bomb.

I also wouldn't trust Brewhemoth with providing a reliable max operating pressure (they give a 'suggested' transfer pressure of 3-4 psi). They also offer a Spunding valve that can be set to 100 psi. Not smart.

If you want to use a Spunding valve for carbonation or pressure-regulation during fermentation, convert a keg to a fermenter:

http://beerandwinejournal.com/krausening-part-3-of-3/

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