Purging necessary for rootbeer?

[Jesseedge]

I usually just cook my 3-5 gallons and pour it into the freshly cleaned corny keg. Set my psi to 30 and wait a week. Should i let it fill and sit for a bit to settle and pull the relief valve to let any o2 out? I don't brew beer so I've never done it before. Any info is appreciated. If I am supposed to purge, detailed instructions would be appreciated. How long after initial fill, how many times, etc.


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[MrFoodScientist]

Anytime I do soda, I never purge. It's my understanding that purging is just to prevent skunking your beer. If you don't have hops in your soda, you should be fine.

On the other hand, I believe that carbonation is dependent on partial pressure of CO2, meaning that any O2 in your system will add to the total pressure, but not to the carbonation. If you're filling to 5 gal, it shouldn't make a difference, if you're filling to 3 gallons with the remaining 2 gallons as headspace, it might factor in, but you likely won't notice it.