How Does Machine Espresso Work?

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

Espresso is made by pushing hot water under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the primary difference.

The Group Head

The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing water into the portafilter and then controlling the pressure of the resulting extraction. There are several different types of group head, each with their distinct advantages and drawbacks. Some are focused on temperature stability, some on pre-infusion options, and others are designed to control the lever. There are even some that contain a variety of features, like the E61, which is considered to be the most popular among baristas for its ability to provide multiple benefits in one package.

As you can see in the image above The group head features several notches to place your portafilter and then twist it by hand to secure it. A gasket of rubber is situated inside the notches to help create a seal while you insert your portafilter. The notches permit the precise placement of the portafilter. This is essential for an even extraction.

Apart from allowing you easily connect your portafilter, the group head is also responsible for maintaining an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is constant for extraction. This is important, as even a small difference in temperature can make the difference between good and excellent espresso.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever that pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure needed for cheap espresso machine extraction. This pressure is built up by pumping water through a heat-exchanger and then through the best ground coffee for espresso machine coffee.

Pumps tend to be cheaper and last longer than piston-driven machines. However, both types of machines can degrade because of frequent use and inadequate cleaning. Pumps are also more complicated mechanically, which could increase prices of even simple models.

Certain espresso machines eliminate the pump completely and instead utilize steam pressure to make espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of water to boiling which could lead to over-extraction. They also have to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize either a rotary or vibration pump, with a vibrating model that uses a vibrating disc to create pressure and a rotary model pushing hot water through the grounds under high speed. Both types of machine can make a great 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 Espresso machines extraction. The steam that is created reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. The steam creates pressure to push through the grounds of the coffee. This creates a foam on top of the espresso. This is a hallmark of a great espresso.

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

The first espresso machines were steam type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they imagine these machines. Semi-automatic machines require you to grind and tamp the beans yourself while the pump controls the water flow and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

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

It also enhances flavor, as it lets you enjoy a longer bloom phase. This lets the beans let their nuances out, and allows for a better extraction.

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

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

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

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