Step 4: Purging
Storing kegs purged with CO2 further ensures that they are clean when it is time to use them.
The fourth step is to purge the kegs with CO2. I like to store my kegs with CO2 in them. Any bacteria that could harm beer will not live in that environment. One at a time, fill the kegs with about five pounds of pressure. Shut the flow of gas from your CO2 regulator and release the pressure from the keg with the pressure release valve (PRV). Fill again. Do this three times. You should now have a keg that is completely void of oxygen.
Now it’s time to design a recipe, brew again, and fill those kegs!
Before filling your clean and sanitized keg, give the pressure relief valve a short pull to make sure you still have pressure. If not, you probably have a leak.