By pump I'm referreng to an electric water pump (mine is 51watts) that actually provides the pressurized water to the grouphead for the shot. It's buried inside the machine, but that's the primary horsepower behind a shot. I lift up the lever on the side of the "Group" and it starts the pump. The pressure quickly rises to about 150psi and that is what forces the hot water through the ground espresso.
If you check out this article - it may answer some questions. Esp. look at the sidebar on the right.
http://coffeekid.com/other/newbies/espresso
For instance - when steaming my machine makes no noise at all (other than the steam hiss).
If you check out this article - it may answer some questions. Esp. look at the sidebar on the right.
http://coffeekid.com/other/newbies/espresso
For instance - when steaming my machine makes no noise at all (other than the steam hiss).