Flatt beer: force carbing pressure vs serving pressure?

[scott_m]

I have kegged and tried force carbing a beer at a temperature of 58-62, had the psi set at 18 (looking to get 2.0-2.3 volumes of CO2). Recently over the past day it's chilled down outside so I put the keg outside and lowered the PSI to compensate for the colder temperatures. Yesterday I lowered the psi to 10 for filling a bottle, and opened it later and it was bubbly; as in the beer didn't lose carbonation (I have the blichman beer gun). I left the keg at 10 psi... Today I tried some and the beer is rather flat. It lost some carbonation. The keg is now around 40f.

I think this post/thread has answered my question as to why the beer was carbonated at first, then went flat:

Well, it's not a mystery at all. If you lower the psi to 10, but the beer is fully carbed at 12 psi, it'll gradually lose some carbonation.

My system is balanced so that at 39 degrees, 12 psi keeps my beers perfectly carbonated.

https://www.homebrewtalk.com/showthread.php?t=202212

Any other thoughts as to force carbing beer when it's warm at high PSI, then serving it cold? I don't have a keezer/fridge to cool down beer at the moment.

Will I lose carbonation if I bottle the beer warm, put in the fridge and serve cold? How can I ensure that the beer in the keg maintains carbonation? Do I have to adjust the PSI back to force carb level after everytime I serve beer?

 

[day_trippr]

You can carb at pretty much any temperature, you just need to set the CO2 pressure accordingly. And your 18 psi was way too low for the typical ale, given the temperature.

Use our favorite carbonation table, find your beer temperature on the Y-axis, run along that row until you find the carbonation level you desire (hint: 2.4-2.5 is middle of the road for most ales) then go up that column to find the correct CO2 pressure to hit that carbonation level.

Left undisturbed on gas, a full 5g corny keg will take a little more than a couple of weeks to reach equilibrium. For the impatient, that can be accelerated via agitation (eg: gently rocking the keg).

"Dispensing pressure" should always hit a spot on the chart that maintains the same level of carbonation. So, if you carbed to 2.4 volumes at 65°F using 27 psi CO2 pressure, and you dispense at, say, 38°F, you want to set the CO2 pressure to a scoche over 10 psi (and you want to have ~10 feet of 3/16" ID beer line between keg and tap, fwiw). This will maintain the desired level of carbonation through the life of that keg.

As for bottles, once you have a fully carbonated beer - at any temperature - if you transfer it to a bottle and cap it without losing much CO2 in the process, the bottle will have the desired carbonation...

Cheers!