When one makes a cup of drip coffee, it is easy to figure out how this machine brews the coffee. Water is pumped from a reservoir into the coffee grounds. This water is then filtered by a paper (or gold) filter and drips in to the carafe. The carafe is sat on a heated plate, which in turn heats up the coffee within the carafe and we have coffee! Espresso on the other hand is a different beast. Being able to compact the equivalent of one cup of coffee into one shot of espresso requires a different brewing mechanism. The Basics of Espresso Espresso machines need the coffee to be ground much finer than the grind of drip coffee. The ground coffee should look and feel like sugar. But be careful: coffee which is grinded too fine will cause the espresso to come out slowly. This results in a bitter cup of espresso. A shot of espresso should take 25-30 at most to brew. The espresso should come out as a thick, dark brown (not black) liquid. If brewed properly, there will be a lighter brown colored foam on the top of the espresso. This layer is the crema and contains a lot of the flavor of the espresso. The Basics of What an Espresso Machine Does to Produce Espresso Fresh, cold water should be poured into the reservoir. The ground coffee is placed into the porta-filter, which is the metal, portable filter of the espresso machine. Once the machine is turned on, the machine will heat up an internal coil of wire. This in turn heats the water as it is pumped into the heating chamber. Once in the heating chamber, the water is pressurized to around 220 psi and then is forced out of the chamber. The pressure is so strong that it can force the water through the grounds and the porta-filter creating a fresh, delightful shot of espresso. | 