Types of Espresso Machines

Espresso is perhaps one of the most popular coffee variations worldwide. Made popular in Milan, Italy during the early part of the twentieth century, it is a very concentrated type of coffee beverage produced by forcing extremely hot water, about 90C in temperature, through coffee under extremely elevated pressure of at least 900 kPa. The coffee that is used for espresso has been previously ground to a consistency that is between very fine and nearly powdery.

Needless to say, in order to make respectable espresso, you would need a good machine. Real espresso is of a thick consistency, definitely much more than that of drip coffee. It also has a greater amount of dissolved solids per volume. In addition to this, the defining characteristic would have to be what is called its crema. This is a layer of foam floating on the surface of this coffee beverage which is of a reddish-brown hue. Of course, the high-pressure process entailed in the brewing leads to a very concentrated shot wherein all of the flavors of a typical cup of drip coffee are packed into one shot. Not surprisingly, espresso makes for a good base for various other coffee beverages, including mocha, cappuccino, latte and macchiato.

Having said, the importance of having the right machine cannot be overstated. Also, with there being several types of machines, it is also important for the self-respecting maker to know the differences among the different machines.

From the time espresso was first brewed in Milan up to the middle part of the 1940s, it was made primarily with the use of steam pressure. These days, this type of machine is called a steam-driven machine, and it is now used primarily for low-cost consumer machines.

Things began to pick up for the espresso machine when the piston-driven type of machine was invented. With this machine, espresso can be produced at a pressure of up to 0.82 to 1.8 MPa. This type of machine was also the first to churn out the crema of the espresso, which was originally regarded as an objectionable waste product but which eventually became its defining characteristic. Also, the piston-driven espresso machine is known for being the source of the colloquial term "pulling a shot", denoting the action of making an espresso, because of the lever characteristic of this machine.

The pump-driven machine is an improved version of the piston-driven machine. Currently, it is the favored type of machine used in espresso bars and restaurants.