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The Complete Guide To Machine Espresso
How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and mind-blowing filter technology to create the perfect cup of coffee. How exactly does it work?

Espresso is made by pushing hot water at high 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

As the name suggests the group head is the place you place your portafilter when making espresso. It disperses the water into the portafilter and regulates the pressure of the extraction. There are several different types of group head each with its own advantages and disadvantages. Some are designed for stability of temperature while others are designed to handle pre-infusion. Some are designed to control the lever. Some have a combination of features, like the E61 that is the standard choice for many baristas due to its ability to offer multiple perks in a single package.

As you can see in the above image the group head is made up of many notches in which you can put your portafilter, then twist it manually to secure it. A rubber gasket is located in the notches to create a seal while you insert your portafilter. The notches on the head permit an exact placement of the portafilter, which is vital to ensure an efficient extraction.

espresso machines for home does not just allow you to put in your portafilter easily but also maintains an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is always at the right level to extract the coffee. This is important because just a few degrees could mean the difference between good and excellent espresso.

The Pump

The motorized pumps that are used in rotary espresso machines provide the nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines that rely on levers. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger before it is shot through the ground coffee in the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines can deteriorate because of frequent use and poor cleaning. Pumps are also more complex mechanically, which can raise the cost of even most basic models.


Certain espresso machines can eliminate the pump entirely and use steam pressure to brew espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of the water to the point of boiling, which can lead to over-extraction. In addition these machines typically have to rebuild their pressure between cups, which requires time and energy.

A majority of espresso machines utilize either a vibration or rotary pump. A vibration model makes use of a rotating disk to generate pressure, whereas the rotating model pushes hot water through the ground at a rapid speed. Both machines can make excellent espresso but rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is the one that is used to heat the water to the ideal temperature to extract. The steam that is created reaches the portafilter, which holds the espresso grounds. It is then pumped into the cup. In this process, the steam causes pressure to push through the grounds of the coffee. This results in a layer crema on top. This is one of the hallmarks of a good espresso.

There are three types of espresso machines, each with a different type of pump and the temperature of the brew. There are many ways to control the strength of the brew and the size of cup that can be made by the machine.

The first espresso machines were steam-based. They used a single boiler to make steam and brew, however the pressure they were able to produce was not very high - two bars of atmospheric pressure at the most. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic device with an electric pump. These are the things people think of when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the flow of water and pressure. This is a fantastic compromise between human control and mechanised consistency.

The Filter

Espresso machines usually use filters that separate the grounds of the coffee from hot water. The filter is also a vital component of the machine's temp control, since it stops overheating.

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

It is important to keep in mind that even the most efficient filter can make a bad cup of coffee. The quality of the beans, and the extraction process remain crucial.

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 the place where the portafilter (the thingy you put the coffee ground into) is placed when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to create steam, which is then pushed through the grounds at high pressure. These kinds of machines tend to be cheaper and easier to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal conditions for brewing because they operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.

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

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