How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the delicious coffee espresso machine we enjoy. What exactly is it?

Espresso is produced 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 main difference.

The Head of the Group

As the name implies the group head is the place you insert your portafilter when making espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure of the extraction. There are many different kinds of group heads each with its particular advantages and drawbacks. Some are designed to provide stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are also some that include a mix of features, such as the E61 that is the standard choice for many baristas due to its ability to offer multiple benefits in one package.

As you can see in the above image the group head is made up of many notches in which you can place your portafilter before twisting it with your hands to secure it. There is also a gasket made of rubber in the notches, which helps create the seal when you insert your portafilter into the machine. The notches on the head allow for a precise position of the portafilter which is crucial for an even extraction.

Apart from allowing you easily connect 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-basket, ensuring that the temperature is always at the right level for extraction. It is important to remember that even a small deviation can make the difference between a decent and a great espresso.

The Pump

The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bar pressure required to extract espresso. This is different from manual piston machines that use a lever. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally less expensive and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to overuse and insufficient cleaning. They also make mechanically complex that can lead to a high price tag on even the simplest models.

Some espresso machines can eliminate the pump completely and make use of steam pressure to make espresso. The drawback is that the boiler that produces steam also raises the temperature of water until it reaches boiling, which can lead to excessive extraction. The machines must also constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines employ an rotary or vibrating pump, which is a vibration model using a rotating disc to create the pressure and an rotary model that pushes hot water through the grounds under high speed. Both types of machines can make excellent espresso, however the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to an ideal temperature to extract. The steam that is produced is then directed to the portafilter, which holds the espresso grounds. The steam is then channeled into the cup. The steam is able to create enough pressure to push the coffee grounds through. This results in a crema on top of the espresso. This is one of the main characteristics of a great espresso.

There are three kinds of De'Longhi Stilosa EC260.BK Espresso Coffee Machine - Premium Quality (a cool way to improve) makers, and they differ in the kind of pump they use and the degree of heat that the coffee is. There are a variety of ways to control the amount of brew, as well as the size of the cup that can be produced by the machine.

The first espresso machines were steam-based. The earliest espresso machines were steam types. 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 common espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine you need to grind the beans and then tamp them by hand. The pump regulates the flow of water and pressure. This is an excellent compromise between human control and mechanized accuracy.

The Filter

Espresso machines typically have a filter that separates the coffee grounds from the hot water. The filter is also a vital component of the temperature control system as it prevents the machine from overheating.

Filters also aid in flavor because it allows for a longer flowering phase. This lets the beans release their flavor and allows for a better extraction.

However it is crucial to remember that even a great filter can result in a poor cup of coffee, De'Longhi Stilosa EC260.BK Espresso Coffee Machine - Premium Quality because the quality of the beans and extraction is still important.

This is where the magic happens, it's what makes an espresso really taste good. The grouphead, sometimes called the brew head, is the place where the portafilter (the thing you put the ground coffee in) is placed when making espresso.

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

In recent times, espresso machines powered by a compressed air compressor have become increasingly popular. They use an air compressor to force hot water into the ground and are much more mobile than electric steam-driven espresso machines.