I have a friend that works at a bar and has asked me to show him how to make hard seltzer. I tried brewing hard seltzer with nutrient and yeast and that was a royal PIA! Anyways, I am just going to mix vodka and RO water in a keg and force carbonate. I'll figure out the flavoring part later. My question is, do I need to worry about purging the air from the headspace of the keg with CO2? Will hard seltzer oxidize? TIA!