I have heard of adding like a half gallon of water during the boiling of the priming suger to ensure you get a full five gallons when bottling. Never have tried this. Is this a good idea? Bad Idea? In either case what impact will priming for five gallons have with only say 4.5 gallons of actual beer? I guess I lose a bit during gravity testing, moving to secondary, etc... Anything that can be done to mininimize the decrease in beer volume?