How Does Machine Espresso Work?

The machine espresso utilizes precise pressure, as well as a filter technology that is awe-inspiring to create the coffee you enjoy. What exactly is it that makes it work?

Espresso is created by forcing hot water under high pressure through finely ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.

The Group Head

The group head is the portafilter that you put in when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are many different kinds of group heads, each with their unique advantages and drawbacks. Some focus on temperature stability, some on pre-infusion features, and others are designed to control the lever. Some come with a combination of both, like the E61. This is a preferred choice for baristas because it offers multiple advantages in a single package.

As you can see from the photo above the head of the group is fitted with several notches. You can place your portafilter in these notches and then turn the head around to secure it. A gasket made of rubber is placed inside the notches, which helps create a seal as you insert your portafilter. The notches allow for precise placement of your portafilter. This is crucial for an efficient extraction.

Aside from allowing you to effortlessly insert 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 note that even a tiny deviation can make the difference between a great and a great espresso.

The Pump

Unlike manual piston machines, that use a lever to pressurize water, the rotary espresso machines use motorized pumps to deliver the nine atmospheric bars of pressure necessary to extract espresso. 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 machines and tend to last longer. However, both types of machine can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, and can add to the cost of even the most basic models.

Certain espresso machines eliminate the pump completely and instead utilize steam pressure to make espresso. This can lead to over-extraction as the boiler that produces steam also heats the water until it comes to a boil. Additionally these machines are often required to rebuild their pressure between cups, which requires time and energy.

Many espresso machines utilize either a rotary or vibration pump, with a vibration model using a vibrating disc to generate the pressure and rotating models that push hot water through the grounds at high speed. Both machines can make great espresso but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the component that heats water to an ideal temperature for extraction. The steam that is produced reaches the portafilter that contains the ground espresso and is then pumped down into the cup. The steam creates pressure and pushes through the coffee grounds. This results in a whipped-up top of the espresso. This is a sign of a great espresso.

There are three kinds of espresso makers. They differ in the type of pump they employ and how hot the coffee is. There are various ways in which the brew can be controlled and the size of the cup the maker can create.

The earliest espresso machines were steam types. The first espresso machines were steam-type machines. This led to the coffee tasting bitter and burnt. The modern espresso machine was invented by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso machine is a semiautomatic one with an electric pump. When people think of espresso and filter coffee machine machines, they imagine 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 a fantastic combination of human control and mechanized 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 part of the temperature control system, because it stops the machine from overheating.

It also improves flavor, as a filter can allow for a longer bloom phase. This helps the beans release their nuances and gives an opportunity for better extraction.

It is important to keep in mind that even the finest filter can result in a bad cup of coffee. The quality of the beans and the extraction process are still crucial.

It's in this area that the magic happens. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you put the portafilter - the thingy that you use to put the coffee grounds in, when making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to produce steam. The steam then pushes hot water into the coffee grounds under high pressure. They are less expensive and easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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