9 . What Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to create the coffee we love. How does it work exactly?

To make an espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However the pressure is the main difference.

The Head of the Group

The group head is the portafilter that you put in when making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are many different kinds of group heads, each with their distinct advantages and drawbacks. Some are specifically designed for temperature stability while others are designed to handle pre-infusion. Others are made to control the lever. There are also some that come with a range of features, such as the E61 one, which is the most popular choice among baristas because of its ability to offer multiple benefits in a single package.

As you can see in the photo above the group head comes with several notches to place your portafilter before twisting it by hand to secure it. A rubber gasket is located within the notches to make a seal when you insert your portafilter. The notches permit precise placement of your portafilter. This is crucial for an even extraction.

The group head not only allows the portafilter to be inserted easily however it also keeps the temperature at a constant level. This is achieved by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant to extract the coffee. This is important because even a small espresso machine difference in temperature can make the difference between good and great espresso.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever to pressurize water, rotating espresso machines rely upon motorized pumps to provide the nine atmospheric bars of pressure required for espresso extraction. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally less expensive and last for longer than piston-driven machines. However, both types of machines can deteriorate because of frequent use and inadequate cleaning. Pumps are also more complicated mechanically, which could increase prices of even most basic models.

Some espresso machines can eliminate the pump entirely and employ steam pressure to create espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of water until it reaches boiling which could lead to excessive extraction. In addition these machines are often required to restore their pressure between cups, which requires time and energy.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model employs a rotating disk to generate pressure, while the circular model pushes hot liquid through the ground at a high speed. Both machines can make excellent espresso, however rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler is the one that will heat the water to the right temperature to extract. The steam that is produced reaches the portafilter which holds ground commercial espresso machine beans and gets funnelled down into the cup. During this process, the steam creates pressure and pushes through the coffee grounds. This results in a layer crema on top. This is one of the main characteristics of a good espresso.

There are three kinds of espresso machines, each having distinct pumps and brew temperature. There are different ways that the brew may be controlled as well as the size of the cup the machine is capable of making.

The first best espresso machine under 500 machines were steam-types. The earliest espresso machines were steam types. This led to the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso maker is a semi-automatic one with an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic machine, you must grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is a great combination of human control and mechanized consistency.

The Filter

Typically, espresso machines have a filter to separate out the coffee grounds as they pass through the hot water. The filter is also a vital component of the machine's temp control, since it stops overheating.

A filter also helps with flavor, as it permits a longer flowering period. This helps the beans release their flavor and gives the chance for better extraction.

However it is crucial to keep in mind that even a good filter can produce a bad cup of coffee, because the quality of the beans and extraction is still crucial.

It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead, also referred to as the brewhead, is where the portafilter (the device you put the ground coffee in) is placed when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds under high pressure. They are less expensive and easier for the user to maintain than pumps-driven models. However, they are limited in their ability to produce the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air compressor to push hot water through the ground and are much more mobile than steam-driven electric espresso machines.