How Do Espresso Machines Work?

A Bit of Espresso Machine Background

According to the Mad Coffee Maker, the first mechanized espresso maker was invented in 1903 and further perfected by a man named Achiles Gaggia, whose eponymous firm is still around today. However, espresso-making is a craft that has been around for thousands of years.

Successful espresso making is the product of many factors, including water and coffee quality, temperature and heat. Even though that latte at Starbucks looks simple, there's a learning curve to being a good barista. Espresso machines are finicky creatures that produce according to the user's ability.

The base functions of all espresso machine models are the same. The machine takes water and heats it until it's at a suitable heat level. The machine will then pass the heated water through the ground coffee, producing espresso. The rest of the water is pressurized and heated to make the hot steam to froth the milk in cappuccino and latte drinks.

A manual espresso machine require that the user handle most of the steps in the drink-making process. This means grinding the beans, tamping the coffee and adding the proper amount of water in the right pressure with the nozzle. For drinks that utilize steamed or frothed milk, there's also the necessity of learning how to use the steam nozzle. To do this, the user pours the milk into a metal container and holds the nozzle on the side, waiting for telltale signs like changes in sound and color to signal readiness.

The Mad Coffee Maker recommends that the beginning barista start off with a manual to truly learn the process of espresso making. This is the best way to see the direct effect of different variables on coffee making and brings about an appreciation of the process.

Most home models are semi-automatic, with the machine doing the heavy lifting of creating suitable water pressure to brew the coffee. The user, however, takes care of the coffee grinding and tamping as well as the finishing. Semi-automatics also have two broilers that control extraction and steaming strength. Commercial models may even refill the metal portafilter with fresh coffee after each use. Some semi-automatics contain internal milk heaters that apply a pre-set amount of pressurized steam to create froth.

Many coffee bars use these mostly hands-off models to make coffee drinks. High-volume cafes find the push-button operation convenient and fast, which is a big help in locations with constant customer flow. However, these machines produce a product that may not be at its best due to lack of customization.

To use an automatic, the barista grinds the coffee, inserts the portafilter, pushes a button and waits. The machines may have settings for one or more cups with different sides for regular and decaffeinated strength. A cup of espresso is produced in seconds. The milk steamer may have a manual knob or a pre-set button, with the barista choosing whatever is simplest at the time. Fully automatic machines are fast, easy to learn and productive but lose the artistic side of espresso making.