Do Not Buy Into These "Trends" Concerning Machine Espresso How Does Machine Espresso Work?

The machine espresso uses precise pressure, as well as a filtering technology that is amazing to make the coffee you love. How exactly does it work?

Espresso is produced by pushing hot water under high 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

The group head is the portafilter that you place in the espresso maker when making it. It distributes water into the portafilter, and controls the pressure of the extraction. There are various kinds of group head each with its distinct advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. discount espresso machines are made to control the lever. Some are a combination, like the E61. This is a very popular choice for baristas because it offers multiple benefits in a single package.

As you can see in the picture above, the group head is fitted with several notches. You can place your portafilter inside these notches, and then twist the head to secure it. A gasket of rubber is situated inside the notches to help make a seal when you insert your portafilter. The notches on the head allow for a precise placement of the portafilter, which is crucial to ensure an efficient extraction.

In addition to allowing you to easily insert your portafilter, the group head is responsible to maintain an even temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is at the right level to extract the coffee. This is important because just a few degrees could make the difference between a good and excellent espresso.

The Pump

The motorized pumps that are used in rotary espresso machines supply the nine atmospheric bars of pressure required to extract espresso. This differs from manually operated piston machines that employ levers. This pressure is generated by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven models, and they tend to last longer, however both types of machines may get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, and can add to prices of even most basic models.

Some espresso machines make use of steam pressure instead of a pump to brew espresso. The drawback of this is that the boiler that produces steam also raises the temperature of the water until it reaches boiling and can result in excessive extraction. In addition these machines typically have to restore their pressure between cups, which requires time and energy.

Many espresso machines make use of a vibration or rotary pump, which has a vibration model using a rotating disc to create the pressure and the rotary model pushing hot water through the grounds at high speed. Both types of machines can make a great espresso, but Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the component that heats water to the ideal temperature for extraction. The resulting steam is then transferred to the portafilter that contains the ground espresso coffee and is then pumped down into the cup. During this process, the steam causes pressure to push through the grounds of the coffee. This creates a foam on top of the espresso. This is a sign of a great espresso.

There are three types of espresso machines, each with distinct pumps and the temperature of the brew. There are different 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 types. They employed one boiler to make both brew and steam, but the pressure they could create was minimal - two bars of atmospheric pressure, at most. The coffee tasted bitter and burned. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso machine is a semiautomatic that has an electric pump. This is what people envision when they think of an espresso machine. With a semi-automatic machine you grind the beans and then tamp them by hand, but the pump is able to regulate the flow of water and pressure. This is a great compromise between human control and mechanized accuracy.

The Filter

Espresso machines typically use filters that separate the grounds of the coffee from hot water. The filter is also a vital part of the temperature control system because it stops the machine from overheating.

A filter also improves flavor since it allows for the beans to flower for a longer period of time. This allows the beans to let their nuances out and provides an opportunity for a better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans as well as the extraction, are still very important.

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

In the steam-driven espresso machine hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds under high pressure. These types of machines are typically less expensive and simpler to maintain than pump-driven models. However, they are limited in their ability to provide the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.


In recent years, compressed air pump-driven espresso machines have been gaining popularity. They utilize an air compressor to force hot water into the grounds and are significantly more portable than steam-driven electric machines.