Here`s another titbit of information that may be of inertest re pressurized kegs
Back in the early days of San Francisco there was little refrigeration to keep kegs in so most of the beer was stored behind the bar
When the barman would change over onto a new keg he would have to pull the spear out of the empty this would usually bring the immediate crowds attention and they would let out a cheer and comment on the stream of co2 coming from the keg and say it looked like steam
This occurs when the co2 rushes from the keg to the atmosphere it lowers it pressure and condenses which give a jet stream appearance
Hench the name Californian steam beer!
Ar beer such marvelous stuff
Cheers speedie