I keg my beer after fermenting hook up about 10-12 pounds CO2 into the Liquid side of the keg, set in the kegerator and forget it for a week or so. Comes out great. Today when I hooked the CO2 to the Liquid side as usual i heard it bubbling through the beer as it pressured up. Here is the NOOB observation... the keg pressured up but as I shook the keg around fitting it into the back corner, I heard more CO2 bubbling into the keg. So i shook around the keg, more bubbling . I did this several times , bubbling every time... Thus the reason everyone calls for pressuring up the keg and rolling it around for 5 minutes.