How long will a keg hold carbonation if it is disconnected from the CO2 tank?

Does the type of keg matter?

  • 1
    You must also hold the keg at the same temp it was carbed at, or else C02 will move into the headspace of the keg and you'll get foamy pulls from the tap that don't make much carbonation.
    – GHP
    Commented May 11, 2012 at 18:46

3 Answers 3


Indefinitely is right assuming your seal is good, but the beer will need to have absorbed CO2 to the point of "equilibrium", meaning it has absorbed all it can for the pressure you have it set at. If this is not the case, the pressure will drop to zero.

Also, It absorbs faster and reaches equilibrium more quickly when the beer is cold.

  • 1
    Why would the pressure reduce to zero if it weren't fully carbonated? If only, say 2 volumes had absorbed into the beer, despite being set at a temperature and pressure that would achieve 3 volumes, why would the beer not retain the 2 volumes of CO2 that it had already absorbed? Commented May 14, 2012 at 15:20

As long as all of seals are good, it should hold pressure indefinitely.


Yes, in theory, it should hold pressure indefinitely. If you don't already, perform a "soap bubble leak test" by pressurizing the keg (10 PSI should do it) then brushing or spraying on a water/ soap solution. If there is a leak, large bubbles will form where the leak is. The solution should be mostly water with a bit of dish soap or something similar. If the solution has too much soap in it, it will bubble just from being applied. I do a quick "spray soap" after I've cleaned and assembled my keg for use but before I sanitize it. It's also a good idea to check the keg connections (ball or pin lock connections) and your hose connections at the regulator and any other transition piece (regulator to tank connection, splitters, ect.).

  • 1
    Star san will also happily bubble wherever a leak is, and most brewers I know already have a bit of that laying around in spray bottles or inside the keg.
    – baka
    Commented May 11, 2012 at 21:32
  • 1
    +1 to starsan. And if you need to open the keg to reseat the lid star san is harmless where a little soapy water will ruin your head retention before the beer is even dispensed.
    – brewchez
    Commented May 11, 2012 at 22:44
  • That is a great idea! Starsan is a little hard to come by in Canada, but it seems worth it to track it down. I usually rinse the soap and sanitize with iodine before using.
    – David PGB
    Commented May 12, 2012 at 21:55

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