Force carb times and volume

[Jaeger]

Odd question that may have been answered before.

Does it take the same amount of time to force carb 2.5 gallons as it does 5 gallons?

I brewed five gallons of Pilsner and decided to bottle half for coworkers to try. I put the other half in the keg and have been force carbing for about 24 hours. Should I expect it to take the same amount of time for half the volume? Logically, it should take half the time because it is half the volume, however I could see it taking the same amount of time because it is still the same volume inside the keg.

Anyway, before I get bogged down with questions, I started force carbing at 30 PSI and will turn it down to about 15 PSI for a few days before dropping it down to serving pressure. Not really shooting for a specific carb level because I made it for me and not to please anyone else.

Thanks for the help

 

[day_trippr]

This is definitely an @doug293cz question, but I'll swag an answer:
Relative time must be about the geometry: surface area * depth. Other factors should cancel out.
If you were to put 2.5 gallons in a 5 gallon corny keg it'd likely reach equilibrium in half the time vs a full 5 gallons.
In the same vein, be careful about burst carbing a half-filled keg. The typical "30 psi for 24 hours" thing could end up a foamy mess...

Cheers!

 

[doug293cz]

@day_trippr is correct - for the same surface area, 1/2 the volume (of beer) will carb in about 1/2 the time. Maybe not exactly, but close. The headspace volume plays no part in time to carb, if CO2 is continuously connected.

Brew on

 

[Jaeger]

Thanks for the replies. I turned off the gas this morning before work and will go check on it tonight when I get home. Hopefully it isn't a foamy mess....