How Does Machine Espresso Work?

Machine espresso employs precise pressure and incredible filter technology to produce the coffee we love. What exactly is it that makes it work?

Espresso is made by forcing 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 Group Head

The name implies, the group head is where you put your portafilter in when brewing espresso. It is responsible for dispersing the water into the portafilter and then controlling the pressure that results from the extraction. There are many different kinds of group head each with its unique advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion features, and others are designed to control the lever. Some include a combination like the E61. This is a preferred choice for baristas as it provides a variety of advantages in one package.

As you can see in the image above the group head is made up of several notches to put your portafilter, then twist it manually to secure it. There is also a rubber gasket that resides inside the notches and helps to create an airtight seal after inserting your portafilter into the machine. The notches permit precise placement of the portafilter. This is essential for an even extraction.

In addition to allowing you to easily insert your portafilter, the group head is also responsible for maintaining a consistent temperature. It does this by cycling hot water through the brew basket, and around the portafilter, making sure that it's always at the correct temperature to extract. It is important to realize that even a tiny differences can make the distinction between a decent and a great espresso.

The Pump

The motorized pumps used in rotary espresso machines supply the nine atmospheric bars of pressure required for espresso extraction. This is different from manual piston machines that use a lever. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically cheaper and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading because of excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which could increase prices of even most basic models.

Some espresso machines use steam pressure instead of a pump to make espresso. This can result in over-extraction because the boiler that produces steam also heats the water until it comes to a boil. Additionally these machines typically have to rebuild their pressure between cups, which requires time and energy.

Many espresso machines utilize the rotary or vibration pump, which has a vibration model using a vibrating disc that generates the pressure and the rotary model pushing 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 break.

The Boiler

The boiler is the element that heats the water to the optimal temperature to extract. The steam created is then directed to the portafilter, which is a container for espresso grounds. It is then pumped into the cup. During this process, steam creates pressure that pushes through the coffee grounds. This results in a layer crema that is then poured over. This is a hallmark of a good espresso.

There are three different types of espresso machines, each with a different type of pump and brew temperature. There are various ways that the brew may be controlled as well as the size of the cup the machine can make.

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

The most popular espresso maker is a semi-automatic machine that has an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine, you need to grind the beans and then tamp them by hand. The pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized quality.

The Filter

espresso capsule machine machines usually use a filter that separates the coffee grounds from the hot water. The filter is also a vital part of the machine's temperature control, as it prevents overheating.

Filters also aid in flavor, as it permits a longer flowering period. This allows the beans to release their nuances, and also allows for better extraction.

However, it is important to remember that even a high-quality filter can make a terrible cup of coffee as the quality of the beans and extraction are essential.

This is where the magic happens, it's the thing that makes an espresso really taste great. The grouphead (also called the brewhead) is where you put the portafilter, which is the thingy which you put the coffee grounds into, when making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight container to make steam. The steam then pushes hot water through grounds of TASSIMO Bosch HAPPY Coffee Machine In Purple/White at high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, compressed air-driven espresso machines have been gaining popularity. They make use of an air compressor to push hot water through the ground. They are also more mobile than electric steam-driven espresso machines.