Under Pressure

[canairyman]

Ok so I’m currently chilling a lager brew
And I appear to have lost nearly half of the initial pressure that was in my king keg pressure barrel, as this is my first success with one of these, is my loss of pressure normal??

 

[DocAnna]

the pressure will always drop with a temperature drop, in part due to contraction of gas at lower temperature, but mainly because CO2 is a lot more soluble in colder liquids. So unless you have a leak - yes it’s normal .

 

[canairyman]

the pressure will always drop with a temperature drop, in part due to contraction of gas at lower temperature, but mainly because CO2 is a lot more soluble in colder liquids. So unless you have a leak - yes it’s normal .

Thanks, I’m pretty sure I don’t have a leak as it was up to nearly 20psi at one point

 

[RoomWithABrew]

Thanks, I’m pretty sure I don’t have a leak as it was up to nearly 20psi at one point

Your statement doesn't rule out a leak at all. All it tells you is the gauge and barrel were at 20 psi.

However 18 C beer at 20psi cooled and stable to 4C would have psig of 8.5 psi.

So your pressure drop can be accounted for by physics as well.

However given the length and number of threads on leaking pressure barrel I'm cautious about climbing off the fence without more information.

Regarding @DocAnna re volume change and temperature ( in a changing pressure system in your case) it's complicated so Charles law / Gay lussac won't really apply.

 

[The Baron]

20psi seems a lot for a Pressure Barrel as they are well know to leak especially above 15psi.
Hopefully you have the co2 absorbed fully into the beer and no leak.