How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How exactly does it work?

mini espresso machine is produced by pushing hot water under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the primary difference.

The Head of the Group

The group head is the portafilter that you put in when making espresso capsule machine. It is responsible for dispersing the water into the portafilter and controlling the pressure that results from the extraction. There are various kinds of group head, each with their own advantages and drawbacks. Some are focused on temperature stability, some on pre-infusion capabilities, while others are designed to control the lever. Some come with a combination of both, like the E61. This is a very popular choice for baristas because it offers multiple advantages in a single package.

As you can see from the picture above, the group head is equipped with several notches. You place your portafilter inside these notches, and then turn the head around to secure it. There is also a gasket of rubber in the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is essential to ensure an efficient extraction.

In addition to allowing you effortlessly insert your portafilter the group head is responsible for maintaining a consistent temperature. This is done by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is at the right level to extract the coffee. It is important to remember that even a few degree deviation can make the difference between a good and a great espresso.

The Pump

In contrast to manual piston machines which rely on a lever that pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure needed to extract espresso. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be more affordable and last longer than piston-driven machines. However, both kinds of machines can degrade because of frequent use and inadequate cleaning. Pumps are also more complicated mechanically, which can raise the price of even the simpler models.

Some espresso machines make use of steam pressure instead of a pump for brewing professional espresso maker. The downside is that the same boiler that produces steam also increases the temperature of water to boiling, which can lead to excessive extraction. The machines must also constantly rebuild their pressure in between cups. This requires energy and time.

Many espresso machines use a rotary or vibration pump. A vibration model employs an oscillating disk to create pressure, while the rotating model pushes hot water through the ground at a rapid speed. Both machines can produce excellent espresso but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is the element that heats the water to the optimal temperature for extraction. The resultant steam then reaches the portafilter that contains the ground espresso coffee and is then funneled down into the cup. The steam creates enough pressure to push the coffee grounds through. This creates a crema on the top of the espresso. This is one of the main characteristics of a good espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and how hot the coffee is. There are a variety of ways in which the brew can be controlled and the size of the cup that the maker can create.

The first espresso machines were steam-based. They used a single boiler to make both brew and steam, but the pressure they could produce was not very high - two bars of atmospheric pressure at most. This resulted in the coffee tasting bitter and burnt. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most common espresso maker is a semi-automatic machine with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine you grind the beans and then tamp them yourself but the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and the mechanized quality.

The Filter

Typically, espresso machines have filters to separate the grounds of coffee as they move through the hot water. The filter is also a crucial element of the temperature control system, as it prevents the machine from overheating.

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

However, it is important to remember that even a top filter can produce a bad cup of coffee, as the quality of the beans and extraction is important.

This is where the magic happens. It's what makes compact espresso machine taste great. The grouphead, often called the brew head, is where the portafilter (the container you place the ground coffee in) is located when you're making espresso.

In a steam-driven home espresso machine machine, hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds with high pressure. These machines are less expensive and easier for the owner to maintain than pumps-driven models. However, they are not as efficient in their ability to provide the ideal brewing conditions, because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, compressed air-driven espresso machines have become more popular. They use an air-compressor to force hot water through the ground and are much more mobile than steam-driven electric espresso machines.