| Determination of CO2 application pressure given volumes of CO2 and temperature |
| Vol CO2 |
2.1 |
2.2 |
2.3 |
2.4 |
2.5 |
2.6 |
2.7 |
2.8 |
2.9 |
3.0 |
3.1 |
| Temp. °F |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
PSI |
| 33 |
5.0 |
6.0 |
6.9 |
7.9 |
8.8 |
9.8 |
10.7 |
11.7 |
12.6 |
13.6 |
14.5 |
| 34 |
5.2 |
6.2 |
7.2 |
8.1 |
9.1 |
10.1 |
11.1 |
12.0 |
13.0 |
14.0 |
15.0 |
| 35 |
5.6 |
6.6 |
7.6 |
8.6 |
9.7 |
10.7 |
11.7 |
12.7 |
13.7 |
14.8 |
15.8 |
| 36 |
6.1 |
7.1 |
8.2 |
9.2 |
10.2 |
11.3 |
12.3 |
13.4 |
14.4 |
15.5 |
16.5 |
| 37 |
6.6 |
7.6 |
8.7 |
9.8 |
10.8 |
11.9 |
12.9 |
14.0 |
15.1 |
16.1 |
17.2 |
| 38 |
7.0 |
8.1 |
9.2 |
10.3 |
11.3 |
12.4 |
13.5 |
14.5 |
15.6 |
16.7 |
17.8 |
| 39 |
7.6 |
8.7 |
9.8 |
10.8 |
11.9 |
13.0 |
14.1 |
15.2 |
16.3 |
17.4 |
18.5 |
| 40 |
8.0 |
9.1 |
10.2 |
11.3 |
12.4 |
13.5 |
14.6 |
15.7 |
16.8 |
17.9 |
19.0 |
| 41 |
8.3 |
9.4 |
10.6 |
11.7 |
12.8 |
13.9 |
15.1 |
16.2 |
17.3 |
18.4 |
19.5 |
| 42 |
8.8 |
9.9 |
11.0 |
12.2 |
13.3 |
14.4 |
15.6 |
16.7 |
17.8 |
19.0 |
20.1 |
| * Chart assumes sea-level altitudes. Add 1 psi for every 2,000 ft. above sea level. |
* Chart Reference
- Based on Data from “Methods of Analysis”, American Society of Brewing Chemists, 5th Edition – 1949 (attached)
- Correlation of pressure versus volumes of CO2 at a given temperature are linear
- y = mx + b was used to determine the pressure at a known temperature and CO2 volume
- Example: at 33ºF and 2.6 volumes of CO2 the line slope is 9.54 and the y-intercept is -15.034, thus
y (CO2 pressure) = m (slope) x (CO2 volumes) + b (y – intercept)
y = 9.54 * 2.6 volumes + (-15.034)
y = 9.8 psi CO2 pressure
Figuring ideal gauge pressure of straight CO2 when carbonation level is not known:
- Set the regulator pressure to 5 psi.
- Tap a fresh keg. Make sure the keg has been in the cooler long enough to be at the cooler temperature.
- Pour a small amount of beer through the faucet.
- Observe the beer in the draught line directly above the keg coupler (with a flashlight if necessary), inspecting for bubbles rising up from the beer in the keg.
- If bubbles are present, raise the regulator pressure 1 psi.
- Repeat steps 3 - 5 until no bubbles are present.
This is the lowest pressure at which the gas in the beer is not escaping. This is your ideal gauge pressure.
Download a PDF of Appendix B (40 KB).
