How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the coffee we love. How exactly does it work?

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

The Head of the Group

As the name suggests the group head is the place you place your portafilter while brewing espresso. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are several different types of group heads each with its own advantages and disadvantages. Some are focused on temperature stability, some on pre-infusion features, and others are designed to control the lever. Some have a combination, like the E61. This is a very popular choice for baristas since it provides multiple benefits in a single package.

As you can see from the above photo the group head is fitted with several notches. You can place your portafilter in these notches, then twist the head to secure it. There is also a gasket made from rubber that resides inside the notches to help create the seal when you insert your portafilter into the machine. The notches on the head permit an exact positioning of the portafilter which is essential to ensure a consistent extraction.

In addition to allowing you to easily place your portafilter in, the group head is responsible for maintaining an even temperature. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it is always at the right temperature to extract. This is crucial, since just a few degrees could make the difference between a good and great espresso.

The Pump

Contrary to manual piston machines which use a lever to pressurize water, rotating espresso machines rely upon motorized pumps that provide the nine atmospheric bars of pressure necessary to extract espresso. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both kinds of machines can deteriorate because of excessive use and poor cleaning. They also add mechanical complexity and can lead to costly prices for even the most basic models.

Some espresso machines employ steam pressure instead of a pump for brewing espresso. This can result in over-extraction because the boiler that produces steam also heats the water to boil. In addition these machines are often required to rebuild their pressure between cups, which requires time and energy.

Many espresso machines utilize an rotary or vibrating pump, which has a vibration model using a vibrating disc to create pressure and a rotary model pushing hot water through the grounds under high speed. Both machines can make excellent espresso however rotary machines espresso tend to be more quiet, durable and less likely to fail.

The Boiler

The boiler is the one that makes the water warm to a temperature that is ideal for extraction. The resultant steam then reaches the portafilter containing ground Espresso Machines Home beans and is then pumped down into the cup. During this process, steam causes pressure to push through the grounds of the coffee. This creates a crema on top of the espresso. This is a hallmark of a great espresso.

There are three kinds of espresso machines, each with distinct pumps and brew temperature. There are different ways in which the brew can be controlled and the size of the cup that the machine can produce.

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

The most popular espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans by yourself however the pump controls the water flow and pressure. This is a great combination of human control and mechanised consistency.

The Filter

cheap espresso machine machines usually use filters that separate the grounds of the coffee from hot water. The filter is also a vital component of the machine's temperature control, as it helps prevent overheating.

It also aids in flavor, since a filter allows for a more prolonged bloom time. This allows the beans to let their nuances out, and allows for better extraction.

It is important to keep in mind that even the most efficient 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 good. The grouphead (also known as the brewhead) is where you put the portafilter, the device that you put the grounds of your coffee into when making espresso.

In the steam-driven espresso and filter coffee machine machine hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds under high pressure. These machines are less expensive and are easier for the user to maintain than pumps-driven models. However, they are limited in their ability to create the perfect brewing conditions since they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

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