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How Does Machine Espresso Work?

The machine espresso utilizes precise pressure, as well as a filter technology that is awe-inspiring to make the coffee you love. How does it work exactly?

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

The Group Head

As the name suggests, the group head is the place you put your portafilter in when making espresso. It disperses water in the portafilter and regulates the pressure during the extraction. There are various kinds of group head each with its particular advantages and drawbacks. Some focus on temperature stability, some on pre-infusion options, and others are designed to control the lever. There are some that have a combination of features, such as the E61 that is the standard choice for many baristas due to its ability to offer multiple benefits in a single package.

As you can see from the picture above, the group head is equipped with several notches. It is possible to place your portafilter in these notches, 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 positioning of the portafilter which is necessary to ensure a consistent extraction.

The group head not only lets you to place your portafilter easily however it also keeps an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew-basket, making sure the temperature is always right to extract the coffee. This is important because just a few degrees could 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, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure necessary for espresso extraction. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven machines and tend to last longer, but both types of machines can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which can increase the price of even the most basic models.

Some espresso machines employ steam pressure instead of a pump in order to brew travel espresso maker home machine (resources). This could lead to over-extraction since the boiler that produces steam also heats the water to boil. Additionally these machines typically have to rebuild their pressure between cups, which takes time and energy.

A large majority of espresso machines employ a rotary or vibration pump. A vibration model utilizes a vibrating disk to generate pressure, while a circular model pushes hot liquid through the ground at a rapid speed. Both machines can make excellent espresso but rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler is what is used to heat the water to the right temperature to extract. The resulting steam is then transferred to the portafilter containing the ground espresso coffee and is then funneled down into the cup. The steam creates pressure to push through the grounds of the coffee. This creates a crema on top of the espresso. This is a sign of a great espresso.

There are three types of espresso makers. They differ in the type of pump they employ and the degree of heat that the coffee is. There are also different ways in which the brew could be controlled, as well as the size of the cup the maker can create.

The first espresso machines were steam-types. They had one boiler to make both brew and steam, but the pressure they could produce was not very high - two bars of atmospheric pressure, at most. This resulted in the coffee machines espresso tasting burnt and bitter. This is the reason why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most common espresso maker is a semi-automatic device that has an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans on your own, but the pump regulates the flow of water and pressure. This is an excellent compromise between human control and mechanised accuracy.

The Filter

Espresso machines typically use filters that separate the grounds of the coffee from hot water. The filter is also an essential component of the temperature control system, because it stops the machine from overheating.

It also helps with flavor, since a filter lets you enjoy a longer bloom phase. This helps the beans release their flavors and provides an opportunity for better extraction.

However it is crucial to remember that even a top filter could result in a bad cup of coffee, as the quality of the beans and extraction is important.

It's in this area that the magic takes place. This is the reason why espresso machine coffee tastes so good. The grouphead, sometimes called the brew head, is the place where the portafilter (the container you place the coffee ground into) is placed when 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 a high pressure. These machines are cheaper and easier for the owner to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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