Final level of carbonation doesn't care about the amount of headspace, but depending on the headspace geometry, the rate of carbonation may be affected. If you fill the beer higher than the constant diameter portion of the keg, the surface area of the beer which can absorb CO2 starts to rapidly diminish, and less area means a slower rate of CO2 absorption.Sorry, I meant with beer. And if I put too much beer in that reduces headspace. If it requires a certain amount of headspace to carbonate properly this could be part of it, though not all, I assume.
Brew on
