# Change in Volumes of CO2 @ Different Temperatures

### Help Support Homebrew Talk:

#### JungMin

##### Well-Known Member
Hi,

If I carbonate a beer at 34ºF and 9psi (giving 2.5 volumes of CO2) and then warm that beer up to 53ºF to serve, what will the resulting volume of CO2 be at the serving temperature?

In other words, my carbonating temperature is 34ºF....How can I calculate the proper psi at that temperature to give the desired VCO2 at serving temperatures?

Thanks.

#### day_trippr

##### "This Space For Rent"
- 2.5 volumes.

- Volumes are volumes. They don't change with temperature...

Cheers!

##### Supporting Member
HBT Supporter
What day_trippr said. Once it's carbonated at a certain number of volumes CO2, it's got that number of volumes in it.

However, when you raise the temp to 53, you'll need to have your pressure set at about 19-20 psi to maintain 2.5 volumes CO2:

http://sdcollins.home.mindspring.com/ForceCarbonation.html

Gonna take a LONG beer line to dispense that properly...

#### carlisle_bob

##### Well-Known Member
Hi

Consider that your serving temperature is not your keg temperature. Your lines, shanks and faucets likely are warmer than your keg. Your glassware and room almost certainly are. Serving temp is what happens when all that equalizes. A digital thermometer is a nice thing for seeing how it all stacks up.

Likely you will have a keg at 40 something degrees to serve at 53. In some cases that could be low 40's. That doesn't impact the volumes of CO2. It does change just how high your keg pressure will be.

Bob