Ask Mr. Wizard

Quick Carb Method To Avoid Overcarbing Keg


Tony Polk - Boca Raton, Florida asks,

I am a first timer trying to force carbonate my keg of Oatmeal Stout. I usually use priming sugar that comes with the kits but this time I wanted to try force to carbonate the keg, and am getting 99% foam. Here are the steps I took:

1. Cold crashed both beer and keg.
2. Set CO2 pressure at 25 psi.
3. Laid the keg on its side and rocked for 200 seconds, disconnected and placed in kegerator for 2hours, and tested. Reduced the keg pressure and set the CO2 pressure to 8 psi.
4. Had about a 2” (5 cm) head, however seemed to have very small bubbles and tasted a little flat.
5. Re-carbonated, this time at 25 psi for 2 hrs. whilst rocking every 20 minutes. Disconnected and let it set for a few hours.
6. Reduced the keg pressure and tried to pour. This time nothing but foam.

I went as far as connecting the gas on the beer in and degassing until foam sprayed out. Pressure is set at 10 psi and my beer still appears to be over-carbonated.
Do I disconnect the gas and purge every hour? Seems my 5-gallon (19-L) batch is down to 3-4 gallons (11.4-15.1 L), and I am still trying to get the pour right. Any suggestions will be greatly appreciated. I have the standard gas hookup purchased from a homebrew store.
Tony Polk
Boca Raton, Florida

In my brewing opinion, the only redeeming quality of the old crank and shake method of beer carbonation is that it may properly “carbonate” beer to a desired level when correctly executed.
Response by Ashton Lewis.