Change from bottling to keg.

You can pressurize with a steady 2 PSI, which at room temp would ultimately add a negligible amount of CO2 (like 0.01 vols, maybe), because when the sugar fermentation kicks in, the regulator will shut off. Admittedly this is based on a guess of when 2 PSI steady state will have been reached, and is something where YMMV.

Or you can do that one burst of CO2 (like 20 PSI) that some people use. That's going to net about a tenth of a volume in the beer once dissolved.

IMO, if you're going to use CO2 to seal the keg this way, these small impacts can be ignored. But if you want to cut back sugar because of them, we're talking about less than 0.3 ounces of sugar reduction for a 5 gallon batch (in the case of the 20 PSI burst) or about 0.03 ounces of sugar reduction for the steady 2 PSI batch. Nowhere near the insane 1/3 to 1/2 reductions recommended by gurus who haven't done the calculations.

100% agree.

 

Edit window expired, but I think 0.01 vols here is a bit low, and probably more like 0.05. Still a guess, and variable. In this case, we're talking about roughly 0.15 ounces of sugar in a 5 gallon batch.

 

. . . and this "over-carbonation" amount will self correct after pouring about 1 beer (1 beer is a WAG, too lazy to do the math on something so unimportant). For the "under-sugared" carbonators out there that end up too low the problem will self-correct in 'bout a day once put on gas. Of course this will be a harsh, sharp-edged molecule as opposed to the smooth round CO2 molecules from re-fermentation (wonder if the two will fight it out?). Me . . . I still abhor a vacuum.

 

If you cut sugar by 1/2 or even by 1/3, it's probably going to take more than a day on gas to make up for it, but I agree that you definitely get there in the end.

 

Personally, I'd prefer to slightly under-carb with sugar and make it up with forced CO2 than over-carb with sugar and have to figure out how to get rid of the extra CO2 in solution. But to each their own.

 

One of the beautiful things about kegging is that, unless you go crazy with the priming sugar, the carbonation level will virtually always correct itself. That's why everybody who has their own idea abut how much, if any, to reduce the priming sugar is correct.