A brief history of Espresso espresso machine

Evolution of espresso machines

The oldest espresso machines work the same way as smaller home espresso machines. Water boils in a boiler, and steam collects in the space left behind. When the valve below the waterline opens, hot water rushes out of the valve and down through the coffee under the strong pressure created by the steam. The first European patent based on this principle was filed between 1821 and 1824. In 1843 Eduard Loysel de Santais improved on the patent and used it for the first time in a large coffee machine. Santais's machine caused a stir at the 1855 Paris Exposition by producing 2000 cups of coffee per hour. Santais's machine can make coffee one pot at a time, but in Santais's machine steam is used not to push hot water directly through the coffee grounds, but to raise the hot water to a suitable height above the coffee grounds, from which it then passes through an elaborate pipe to the coffee grounds, using the weight of the hot water itself rather than the pressure of the enclosed steam to complete the extraction.

The first espresso machine of the new century

It wasn't until the early twentieth century that Luigi Bezzera, a Milanese, patented a restaurant machine that used the pressure created by steam in an enclosed space to drive water directly through ground coffee. Bezzera's machines creatively use multiple "water and steam" sets at the same time to put freshly extracted coffee directly into the coffee cup.

In many ways, Bezzera's machines provided much of the basic structure for espresso machines throughout the twentieth century. Take a look at the diagram below. These machines reduce the size of the coffee filter and increase the number of valves. After this adjustment, the coffee machine can make multiple cups of coffee simultaneously and separately, instead of making a whole pot of coffee at a time. Also, as now, espresso operators put spoonfuls of finely ground, deep-roasted coffee powder into a small metal filter. The filter is embedded in a container called a brew group that protrudes from the body of the coffee machine. When the operator opens the valve (or, in more modern machines, pulls the handle or presses the button), the hot water passes through the coffee under intense pressure and into the cup.

Early espresso machines looked like sparkling steam engines pointing to the ceiling. The round tank is designed to stand upright and is covered with beautifully decorated coffee nozzles, valves and pressure gauges. Until World War II, these "coffee towers" decorated with eagles represented the mainstream image of European coffee. After the war, Italians wanted stronger coffee to complement their Vespas, satisfying their thirst for higher speeds.

Mid-century, Gaggia's breakthrough

In 1948 Achilles Gaggia built the first modern Espresso machine. In Gaggia's final design, the tank was placed on one side of the machine, hidden in a streamlined metal box somewhat resembling a modern Danish jukebox. The recommended valve in the older machines was replaced by a spring-loaded piston, which pushed the water through the coffee faster and more forcefully. The operator presses down on a long metal lever. The lever in turn compresses the spring-loaded piston, which drives a volume of hot water slowly through the coffee while the lever is reset. A spring-loaded piston allows water to flow through coffee at a pressure that is now considered ideal for Espresso extraction: a minimum of nine atmospheres, or nine times the normal pressure produced by the Earth's atmosphere. By contrast, prewar steam pressure machines could provide only a meager 1.5 atmospheres.

Espresso machines in the computer age

In the 1960s, when lever-driven espresso machines became popular and became the signature show item of espresso bars, less exciting and more automated ways of driving hot water through coffee grounds began to emerge. In these machines, which did not have a joystick, the earliest designs centered on pumps. The current machine heats the water used to extract coffee separately from the main tank, controls water temperature and pressure more precisely, and incorporates the latest in 20th century technology, a digital reader.

These push-button machines take the streamlined look to the extreme, with all the construction hidden away in separate, elegant, enamel-decorated chrome yellow containers. All machines have one thing in common: the operator does not have to rely on a long joystick, but only needs to press a button. Because many processes are automated, push-button machines make it easier for beginners to operate, but they don't always make good Espresso. In the better coffee shops in the San Francisco Bay Area, it is still customary to use pump piston machines to make coffee. For experts, piston coffee machines can give baristas maximum control over the entire extraction process.