Calculating vols of co2

Discussion in 'General Brewing Discussions' started by Retired trucker 2014, Sep 3, 2020.

  1. Retired trucker 2014

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    I'm going to try pressure fermenting an American Premium Lager but can't find any info on what the vols of co2 will be. I will ferment at 20 psi and at about 60°f. Approximately what will the vols of co2 be when I bottle?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Go for about 2.75 or a bit higher: Carbonation makes up for the lack of body in that style.
     
  3. thunderwagn

    thunderwagn Well-Known Member

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    What is your plan for bottling if pressure fermenting?
     
  4. Nosybear

    Nosybear Well-Known Member

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    Good point. Get a carbonation chart or calculator - your beer will be carbonated at the temperature and pressure of fermentation. You'll want to overcarbonate a bit for bottling which might just be cranking up the pressure on the fermentor.
     
  5. Retired trucker 2014

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    Thats what I am looking for is a calculator to tell what the disolved co2 is if fermented at a certain psi and temp. Maybe I'm blind but can't find in BF calcs.
     
  6. Retired trucker 2014

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    Just made a counter pressure filler and was going to use it if the beer is gassy. I don't want to add anymore sugar to prime.
     
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  7. Retired trucker 2014

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    Ok so I found a forced carbonation chart . This is the chart you spoke of? If so the way I read it if I reduce my ferment temp to 55°f and up the pressure to 23psi , when the beer is finished in 14 days it should be at 2.69 vol of co2. Then I can bottle and lager in the bottle? Or do I leave in the unitank under pressure for the lagering period? It would seem to me that this could cause over carbonation.
     
  8. Yooper

    Yooper Administrator
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    Can you get the keg cold? Bottling warm beer is a foaming mess, but at 2.69 volumes it will be an explosive foamy mess.
     
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  9. thunderwagn

    thunderwagn Well-Known Member

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    #9 thunderwagn, Sep 3, 2020
    Last edited: Sep 3, 2020
    Let me check my last recipe. Brewfather gives you the volume of co2 for the pressure, temp. and number of days. 23 is to high in my opinion. Your yeast very well could stop working and I've read the to much pressure will start giving off flavors. I typically go 15-17 max and I'm over 5000' above sea level.

    Here was my last brew under pressure which is pretty typical for all my brews.

    Fermentation

    Primary — 65 °F — 16 PSI — 14 days
    Carbonation: 2.4 CO2-vol

    I've never checked if the same keg and temp charts work the same as fermenting under pressure.

     
  10. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    I pressure ferment all my lagers. I set the spunding valve to 7 PSI and vent the co2 through a beer bottle with water in it ( I vent through a bottle mostly to monitor fermentation). After 7 days or so at 45-48F/ 7 PSI the air lock activity slows, I raise the temp to 55F and the pressure to about 25 PSI and let it buck. If you raise it to 62-68, then raise the pressure to 28-30 PSI. The beer will finish in about 2 days, but the air lock activity continues for longer since the beer is still de-gassing. After about a week of 25 PSI (14 days total), I crash the beer to 32F and 24 hours later I taste and check the carbonation level and adjust if need be.The beer will continue to de-gas for longer than 14 days and it looks like it's still fermenting, you can check you gravity at that point, but I've done it so many times I don't bother.

    It's not very scientific, but the spunding valve acts as gas regulator. You don't need to be too worried about it, it can be adjusted after crashing. I let the beer lager in the uni-tank and taste it as it ages. After a while, I transfer it to a keg. I could just as well bottle it from the uni-tank, but I prefer the beer to be in a keg.
     
  11. Nosybear

    Nosybear Well-Known Member

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    Look for a carbonation chart - they're all over the internet. There's no difference between pressurized fermentation and carbonation when it comes to dissolved CO2.
     
  12. thunderwagn

    thunderwagn Well-Known Member

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    Sounds like a solid method.
     
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