Bar(psi) vs. Volumes of CO2

Discussion in 'General Brewing Discussions' started by sbaclimber, Sep 28, 2020.

  1. sbaclimber

    sbaclimber Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    869
    Likes Received:
    337
    Trophy Points:
    63
    Location:
    Germany
    Reeeeeaaaaaallllllyyyy stupid question here, but even though I am not too bad at grasping mechanical engineering, things like pressure have always been a bit "out there" for me...
    As I understand it, if the pressure within a vessel remains constant as it is cooled the amount of CO2 contained within the liquid increases (assuming there is a source of CO2).
    If this is correct, and I have a pressure release valve on said vessel (in this case a 5L party keg) set to 2.5 bar, what happens if I cool the keg post conditioning? Will the CO2 in suspension increase or stay the same?
    I ask, because I have a couple kegs in the basement right now which are fully conditioned and at ~15°C. By the time they are tapped, it will be quite a bit colder, and I am curious if there will potentially be more CO2 absorbed or if it will remain constant...
    Theoretically, the pressure within the keg will even decrease if the temperature drops enough(?)
     
  2. Yooper

    Yooper Administrator
    Staff Member

    Joined:
    Nov 16, 2013
    Messages:
    2,485
    Likes Received:
    1,564
    Trophy Points:
    113
    Gender:
    Female
    Occupation:
    Happily retired
    Location:
    Upper Michigan/Florida
    In a sealed vessel, the carbonation level won't change.
     
    sbaclimber likes this.
  3. sbaclimber

    sbaclimber Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    869
    Likes Received:
    337
    Trophy Points:
    63
    Location:
    Germany
    Cool, I guess it is only "sealed" in one direction, but I am very excited to tap the first keg next week and see if it has worked. :D
     
  4. Yooper

    Yooper Administrator
    Staff Member

    Joined:
    Nov 16, 2013
    Messages:
    2,485
    Likes Received:
    1,564
    Trophy Points:
    113
    Gender:
    Female
    Occupation:
    Happily retired
    Location:
    Upper Michigan/Florida
    When you do tap it, and hook it up to the gas to dispense, you'll need to have the proper bar set for the carb level at the current temperature, to replace the gas as the beer is served. But don't overthink it- it's pretty intuitive when you're doing it.
     
  5. sbaclimber

    sbaclimber Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    869
    Likes Received:
    337
    Trophy Points:
    63
    Location:
    Germany
    ah....if only I had something that fancy! ;)
    It is just a standard party keg, which is basically a 5L bottle. Once tapped, it has got to be emptied. :p
     
    Yooper and Craigerrr like this.
  6. Frankenbrewer

    Frankenbrewer Well-Known Member

    Joined:
    Jul 19, 2019
    Messages:
    458
    Likes Received:
    690
    Trophy Points:
    93
    Location:
    Connecticut
    Wouldn't you need to release the initial pressure in the keg before you connect to your serving CO2 if your regulator pressure is at serving say 10 PSI?
     
  7. Craigerrr

    Craigerrr Well-Known Member

    Joined:
    Mar 14, 2018
    Messages:
    4,700
    Likes Received:
    6,899
    Trophy Points:
    113
    I normally disconnect the gas, release the pressure in the geg, set regulator to serving pressure, then reconnect gas.
     
  8. sbaclimber

    sbaclimber Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    869
    Likes Received:
    337
    Trophy Points:
    63
    Location:
    Germany
    You all have "real" kegs. :p
    I've got a couple of these...
    [​IMG]
    ....basically a 5L bottle. I just plugged the top with a 2.5bar pressure release bung for conditioning. I could pump in CO2 during serving, but seeing as it will be emptied within an evening, I just got a hand pump to maintain a bit of pressure and hopefully prevent the beer from going too flat before the "keg" is empty.
     
    Trialben and Craigerrr like this.
  9. Donoroto

    Donoroto Member

    Joined:
    Jun 21, 2020
    Messages:
    62
    Likes Received:
    56
    Trophy Points:
    18
    Location:
    Atlanta
    All the more reason to have friends over to help you drink it.
     
    Trialben and sbaclimber like this.
  10. sbaclimber

    sbaclimber Well-Known Member

    Joined:
    Jul 13, 2012
    Messages:
    869
    Likes Received:
    337
    Trophy Points:
    63
    Location:
    Germany
    Worth repeating here...
    Just tapped my very first "keg". The 2.5 bar bung seems to have done the trick. 1st glass is perfect! :)
    CAL1.jpeg
     
    thunderwagn and Megary like this.

Share This Page

arrow_white