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20 Trailblazers Setting The Standard In Machine Espresso
How Does Machine Espresso Work?

Machine espresso uses precision pressure and amazing filter technology to make the perfect cup of coffee. How exactly does italian espresso machines work?

Espresso is made 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 main difference.

The Group Head

The group head is the portafilter that is inserted when you are making espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure of the extraction. There are various kinds of group heads, each with their own advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion capabilities, and still others are designed to control the lever. Some have a combination, like the E61. This is a favorite among baristas because it offers multiple benefits in one package.

As you can see in the photo above, the group head has numerous notches that you can place your portafilter and then twist it with your hands to secure it. A gasket made of rubber is placed inside the notches to help create a seal while you insert your portafilter. The notches permit precise placement of the portafilter. This is essential for an efficient extraction.

In addition to allowing you to easily connect your portafilter, the group head is also responsible to ensure that the temperature remains even. This is done by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is constant for extraction. It is crucial to keep in mind that even a small variation can mean the difference between a good and great espresso.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever that pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure that are required to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven machines and tend to last longer. However, both types of machine can be damaged by excessive use and inadequate cleaning. They also make mechanically complex and can lead to a high price tag on even the most basic models.


Some espresso machines use steam pressure instead of a pump to brew espresso. This can cause over-extraction because the boiler that makes steam also heats the water to boil. They also have to constantly rebuild their pressure between cups. This takes energy and time.

Many espresso machines employ the rotary or vibration pump, with a vibration model using a vibrating disc to create pressure, and an rotary model that pushes hot water through the grounds at high speed. Both machines produce great espresso however rotary machines tend to be more stable, quieter and less likely to break.

The Boiler

The boiler is the element that heats the water to the ideal temperature to extract. The steam that is produced will eventually reach the portafilter, which is a container for espresso grounds. It is then pumped into the cup. In this process, the steam causes pressure to push through the coffee grounds. This results in a crema on the top of the espresso. This is one of the main characteristics of a good espresso.

There are three types of espresso makers, and they differ in the type of pump they employ and how hot the brew is. There are various ways in which the brew could be controlled and the size of the cup the machine can make.

The first espresso machines were steam-type. They utilized only one boiler to make both steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure, at most. The coffee tasted bitter and burned. This is the reason why Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most commonly used espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they think of these machines. With a semi-automatic espresso machine, you need to grind the beans and then tamp them by hand. However, the pump regulates the flow of water and pressure. This is a perfect compromise between human control and mechanized reliability.

The Filter

Typically, espresso machines employ a filter to separate out the coffee grounds as they pass through the hot water. The filter is also an essential element of the machine's temperature control, as it prevents overheating.

A filter can also help with flavor since it allows for a longer flowering period. This allows the beans to release their flavors, and also allows for better extraction.

However, it is important to remember that even a great filter can make a terrible cup of coffee, because the quality of the beans and extraction is important.

It's in this area that the magic takes place. This is the reason why espresso tastes so delicious. The grouphead, sometimes referred to as the brew head, is where the portafilter (the device you put the coffee grounds into) is placed when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to make steam. The steam then pushes hot water through the coffee grounds under high pressure. These kinds of machines are usually less expensive and easier to maintain than pumps-driven models. They are however limited to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machines driven by compressed air-pump are becoming increasingly popular. They use an air compressor to force hot water through grounds, and are far more portable than electric steam-driven machines.

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