The 10 Scariest Things About Machine Espresso How Does Machine Espresso Work?

The machine espresso utilizes precise pressure, as well as a filtering system that is awe-inspiring to create the coffee you enjoy. What exactly does it work?

To make an espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Group Head

As the name suggests, the group head is the place you place your portafilter while brewing espresso. It distributes water into the portafilter and controls the pressure of the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are built to control the lever. There are also some that contain a variety of features, like the E61, which is considered the classic choice among many baristas due to its ability to offer multiple benefits in one package.

As you can see in the picture above, the group head is equipped with several notches. You place your portafilter inside these notches, and then twist the head to secure it. A rubber gasket is located within the notches to create a seal while you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is essential to ensure a consistent extraction.

In addition to allowing you effortlessly 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 basin, ensuring that the temperature is at the right level for extraction. This is important because even a few degrees can mean the difference between good and great espresso.

The Pump

Contrary to manual piston machines that use a lever to pressurize water, the rotary espresso machines use motorized pumps that provide the nine atmospheric bars of pressure needed to extract espresso. The pressure builds by drawing tap water from a reservoir and pumping it through a heat exchanger prior to being shot through the ground coffee in the group head.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both kinds of machines can degrade because of frequent use and inadequate cleaning. They also add mechanical complexity, which can result in an expensive price for even the most basic models.


Some espresso machines remove the pump entirely and employ steam pressure to create espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of water to the point of boiling which can cause over-extraction. These machines also have to constantly rebuild their pressure in between cups. This requires energy and time.

Many espresso machines make use of an rotary or a vibration pump. A vibration model uses the vibrating disk to create pressure, while the rotary 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 what makes the water warm to the perfect temperature for extraction. The steam that is produced reaches the portafilter containing the ground espresso and is then funneled down into the cup. In this process, the steam causes pressure to push through the grounds of the coffee. This results in a layer crema that is then poured over. This is a hallmark of a good espresso.

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

The earliest espresso machines were steam type. They utilized one boiler to create steam and brew, however, the pressure they could produce was not very high - two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most popular espresso machine is a semiautomatic that has an electric pump. These are the things people think of when they think of an espresso machine. With a semi-automatic machine you need to grind the beans and then tamp them by hand. However, the pump is able to regulate the flow of water and pressure. This is an excellent compromise between human touch and the mechanized accuracy.

The Filter

Espresso machines typically have filters that separate the grounds of coffee from hot water. The filter is also a vital component of the machine's temp control, as it prevents overheating.

espresso coffee machines improves flavor, as it lets you enjoy a longer bloom phase. This helps the beans to release their flavors and provides the chance for better extraction.

However it is crucial to keep in mind that even a good filter can produce a bad cup of coffee as the quality of the beans and extraction is vital.

It's in this area that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead, sometimes referred to as the brew head, is where the portafilter (the container you place the ground coffee in) sits when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to create steam. Steam then pushes the hot water through the grounds at a high pressure. These types of machines are usually cheaper and easier to maintain than pump-driven models. They are however limited for creating 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, compressed air pump-driven espresso machines have been gaining popularity. They use an air compressor to push hot water across the ground. They are also more mobile than electric steam-driven espresso machines.