The Steam Espresso & Cappuccino Machines uses an exclusive steam/boiler to quickly heat water until steam is produced. The steam creates pressure to force the water into the filter holder and through the coffee grounds to brew the espresso directly into the glass carafe. When the espresso has reached the bottom line marking on the glass carafe, you can stop brewing and switch to froth milk. When you finish frothing, turn the selector switch back to the coffee brewing position.