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How Does Machine Espresso Work?

The machine espresso utilizes precision pressure, and a filter technology that is awe-inspiring to make the coffee you enjoy. What exactly does it work?

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

The Group Head

As the name implies, the group head is the place you place your portafilter while brewing espresso. It is responsible for dispersing water into the portafilter and then controlling the pressure of the extraction. There are several different types of group head each with its unique advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion features, and others are designed to control the lever. Some have a combination, like the E61. This is a favorite among baristas since it provides multiple advantages in a single package.

As you can see in the above photo, the group head is fitted with several notches. You place your portafilter inside these notches, and then twist the head to secure it. There is also a gasket made of rubber which is located inside the notches and helps to create the seal when you insert your portafilter into the machine. The notches on the head allow for a precise location of the portafilter which is necessary for espressomachines an even extraction.

Apart from allowing you easily place your portafilter in, the group head is also responsible to maintain an even temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is at the right level for extraction. This is important, as just a few degrees could be the difference between a excellent and great espresso.

The Pump

Contrary to manual piston machines which rely on a lever that pressurize water, Rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure needed to extract espresso and filter coffee machine. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are generally less expensive than piston-driven models, and they tend to last longer, but both types of machine can degrade with overuse and insufficient cleaning. Pumps are also more complex mechanically, which can increase the cost of even the most basic models.

Some espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of the water until it reaches boiling and can result in over-extraction. In addition these machines are often required to restore their pressure between cups, which takes time and energy.

A majority of espresso machines utilize either a vibration or rotary pump. A vibration model utilizes a rotating disk to generate pressure, whereas a Rotary model pushes hot coffee through the ground at a rapid speed. Both machines produce great espresso however rotary machines tend to be more quiet, durable and less likely to fail.

The Boiler

The boiler is the component that heats the water to the ideal temperature for extraction. The steam that is produced reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then funneled into the cup. During this process, the steam creates pressure that pushes through the grounds of the coffee. This creates a layer crema that is then poured over. This is a hallmark of a great espresso.

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

The first espresso machines were steam-types. The first espresso machines were steam-type machines. This resulted in the coffee tasting burnt and bitter. This is why Milanese producers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most well-known espresso maker is a semi-automatic machine 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, but the pump regulates the water flow and pressure. This is an excellent compromise between human touch and the mechanised accuracy.

The Filter

Espresso machines typically use a filter that separates the grounds of the coffee from hot water. The filter is also a crucial element of the temperature control system since it helps prevent the machine from overheating.

A filter also helps with flavor because it allows for a longer flowering phase. This lets the beans release their flavor and improves extraction.

It is important to remember that even the finest filter could result in a poor cup of coffee. The quality of the beans, and the extraction process remain vital.

It's here that the magic happens. This is the reason why espresso tastes so delicious. The grouphead (also known as the brewhead) is where you place the portafilter, the device which you put the grounds of coffee into while making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to create steam, which then pushes the hot water through the grounds at high pressure. These kinds of machines are typically cheaper and easier to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to push hot water across the ground and are more mobile than electric steam-driven espresso machines.