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A Provocative Remark About Machine Espresso
How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to create the coffee we love. What exactly is it that makes it work?

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

The Head of the Group

The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure of the extraction. There are numerous kinds of group heads, each with its own advantages and drawbacks. Some are designed for stability of temperature while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are even some that have a combination of features, like the E61, which is considered the classic choice among many baristas due to its ability to provide multiple benefits in a single package.

As you can see in the image above, the group head is fitted with a variety of notches. The portafilter is placed in these notches and then turn the head around to secure it. A rubber gasket is located inside the notches to help create a seal as you insert your portafilter. The notches on the head allow for an exact positioning of the portafilter which is crucial for a consistent extraction.

The group head is not just able to allow you to place your portafilter easily, but it also maintains an even temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is constant to extract the coffee. It is important to realize that even a slight deviation can make the difference between a great and a great espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bars of pressure required to extract espresso. This is different from manually operated piston machines that employ a lever. This pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading because of excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which can increase prices of even simplest models.

Certain espresso machines eliminate the pump entirely and employ steam pressure to create espresso. This could lead to over-extraction since the boiler that produces steam also heats the water to boil. Additionally these machines typically have to restore their pressure between cups, which takes time and energy.

A majority of espresso machines use the rotary or vibration pump, which is a vibration model using a vibrating disc to generate the pressure and a rotary model pushing hot water through the grounds at high speed. Both types of machines are capable of producing excellent espresso, but Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler makes the water warm to the perfect temperature for extraction. The steam that is created will eventually reach the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a whipped-up top of the espresso. This is a hallmark of a great espresso.

There are three types of espresso makers. They differ in the kind of pump they use and the degree of heat that the coffee is. There are various ways to control the brew and the size of cup that can be made by the machine.

The earliest espresso machines were steam-based. They used a single boiler to make both brew and steam, however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason why Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most well-known espresso maker is a semi-automatic device with an electric pump. This is what people envision when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the water flow and pressure. coffee machine espresso is an excellent compromise between human touch and mechanized consistency.

The Filter

Typically, espresso machines use filters to separate the grounds of coffee as they move through the hot water. The filter is also an essential part of the machine's temperature control, since it stops overheating.

A filter also improves flavor since it allows for a longer flowering period. This allows the beans to release their nuances and gives an opportunity for better extraction.

However, it is important to keep in mind that even a top filter can make a terrible cup of coffee, as the quality of the beans and extraction is still important.


It's here that the magic occurs. This is what makes espresso taste so delicious. The grouphead, also called the brew head, is the place where the portafilter (the device you put the coffee grounds into) is located when you're making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight container to make steam. The steam then pushes hot water through grounds of coffee under high pressure. These kinds of machines are usually less expensive and simpler to maintain than pump-driven models. However, they are not as efficient in their ability to produce the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.

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