Espresso and Its Machines

Espresso has become a staple of coffeehouses, cafes, and many restaurants. To make espresso, coffee beans are ground to an extremely fine powder. Hot water, under high pressure, is forced through the roasted coffee. This produces a rich, flavorful, and almost syrupy beverage.

The coffee is brewed fast. As soon as the water makes contact with the coffee, it drips rapidly into the cup. Espresso is served fresh. When you order an expresso, most coffeehouses ground the beans just before brewing for each cup. This is the best method because when it is made from preground coffee and left to sit in an urn or pot, it loses its flavor and aroma.

You can make espresso at home. The machine used to brew espresso is different from the one used to regularly brew coffee. Commercial machines and home machines work on the same principle: water is heated to boiling inside a closed tank. There is a space at the top of the tank where steam gathers. When the valve is open below the water line, the pressure of the steam trapped at the top of the tank forces hot water out of the valve and down through the coffee.

In 1843, Eduard Loysel de Santais demonstrated his machine at the Paris Exposition of 1855. It produced two thousand cups of coffee an hour. The machine only brewed one pot at a time and used steam pressure to raise the water above the coffee where it then descended through an elaborate system of tubes to the coffee. The weight of the water applied the pressure.

Luigi Bezzera of Milan patented a machine in the early twentieth century that used the pressure of trapped steam to directly force water through ground coffee. The freshly brewed coffee was forced directly into a cup. This machine is the forerunner of the espresso machines of the twentieth century. This early machine had a number of valves which enabled them to produce several single cups of coffee simultaneously.

The modern espresso machine is based on the design of Achille Gaggia. Gaggia made innovations in the water tank and used a spring-powered piston to push the water through the coffee faster and harder.

Today, there are two types of espresso machines. One design incorporates a hydraulic pump which is basically a hands-free operation. The other is based on spring-powered piston that uses a handle to force the hot water through the coffee at just the right pressure. This method gives the operator more control over the brewing process.

Most coffeehouses use the hydraulic pump machines. The operator pushes a button or trips a switch. It is easy to use and is commonly the type purchased for home use. There are companies that manufacture a machine for the home that uses a handle such as the Italian company LaPavoni.