10 Tell-Tale Warning Signs You Should Know To Look For A New Machine Espresso How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the delicious coffee we enjoy. But how exactly does it work?

Espresso is made by pushing hot water under pressure through finely-ground coffee. The process is similar to making drip coffee, however the main difference lies in the pressure.

The Head of the Group

As the name implies, the group head is the place you put your portafilter in when making espresso. It disperses water into the portafilter, and regulates the pressure of extraction. There are many different types of group heads each with its own advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. There are also some that include a mix of features, such as the E61 that is the most popular choice among baristas due to its capacity to offer multiple benefits in one package.

As you can see in the image above the group head comes with many notches in which you can place your portafilter and then twist it with your hands to secure it. There is also a gasket made from rubber that resides inside the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is crucial for an efficient extraction.

The group head does not just allow you to place your portafilter easily however, it also keeps the same temperature. This is done by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is always 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 decent and a excellent 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 builds up by removing 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 cheaper and last longer than piston-driven machines. However, both kinds of machines can degrade because of excessive use and insufficient cleaning. They also make mechanically complex and can lead to an expensive price for even the most basic models.

Some espresso machines use steam pressure instead of a pump to make espresso. The drawback of this is that the boiler that produces steam also raises the temperature of the water to the point of boiling and can result in excessive extraction. In retro espresso machine , these machines frequently have to rebuild their pressure between cups, which requires time and energy.

Many espresso machines make use of a rotary or vibration pump. A vibration model uses an oscillating disk to create pressure, while the rotary model pushes hot water through the ground at a fast speed. Both machines can make great espresso, however rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is what will heat the water to a temperature that is ideal to extract. The resulting steam reaches the portafilter, which contains the ground espresso coffee, and is then pumped down into the cup. The steam causes enough pressure to push the grounds of the coffee through. This results in a layer crema on top. This is one of the main characteristics of a great espresso.


There are three kinds of espresso machines, each having different types of pumps and the temperature of the brew. There are different ways to control the amount of brew, as well as the size of cup that can be produced by the machine.

The first espresso machines were steam-type. They had 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 burnt. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most common espresso machine is a semiautomatic with an electric pump. These are what people imagine when they think of an espresso maker. If you have a semi-automatic machine you have to grind the beans and tamp them by hand. However, the pump provides regulated water flow and pressure. This is a perfect combination of human control and mechanised consistency.

The Filter

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

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

It is important to remember that even the best filter could result in a poor cup of coffee. The quality of the beans, and the extraction process are still crucial.

This is where the magic happens, it's what makes espresso taste good. The grouphead (also called the brewhead) is where you place the portafilter, the thingy which you put the coffee grounds into, when making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight container to produce steam. The steam then moves hot water through the grounds of coffee at high pressure. These machines are less expensive and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the perfect brewing conditions since they operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.

In recent times, espresso machines powered by a compressed air compressor have become increasingly popular. They use an air compressor to force hot water through the grounds, and are far more portable than steam-driven electric machines.