I have a lot of beer to keg and carbonate. I have been fairly successful with setting the pressure at 30 PSI and letting it set for 18-24 hours ....i just checked a batch I have had on gas for 18 hours and it is flat as a pancake? I know temperature effects carbonation, but do other things affects it? This is a chocolate vanilla oatmeal stout ( tastes pretty good even flat) would all of the extra "stuff" make it harder to carb?