How Does Machine Espresso Work?

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

Espresso is produced by pushing hot water at high pressure through finely ground coffee. The process is similar to making drip coffee. However the pressure is the main difference.

The Head of the Group

The group head is the portafilter that you insert when brewing espresso. It disperses the water into the portafilter and regulates the pressure of the extraction. There are many different kinds of group head, each with their own advantages and drawbacks. Some focus on temperature stability, some on pre-infusion capabilities, and still others are designed to control the lever. Some include a combination like the E61. This is a very popular choice for baristas due to the fact that it has multiple advantages in a single package.

As you can see in the above photo, the group head has a number of notches. You place your portafilter in these notches and then twist the head to lock it. There is also a rubber gasket in the notches to help create the seal when you insert your portafilter into the machine. The notches allow for precise placement of the portafilter. This is vital for an efficient extraction.

The group head does not just allow you to insert your portafilter easily, but it also maintains an even temperature. It does this by circulating hot water through the brew pan and around the portafilter, making sure that it's always at the correct temperature for extraction. This is crucial, since even a small difference in temperature can mean the difference between good and excellent espresso.

The Pump

The motorized pumps in rotary espresso machines provide the nine atmospheric bars of pressure required to extract espresso. This differs from manual piston machines that rely on levers. The pressure builds by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to it is shot through the ground coffee inside the group head.

Pumps are generally more affordable and last longer than piston-driven machines. However, both types of machines can degrade due to excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which can increase prices of even simpler models.

Certain espresso machines utilize steam pressure instead of a pump for Espressomachines brewing espresso. This can lead to over-extraction as the boiler that produces steam also warms the water to boil. The machines must also constantly rebuild their pressure in between cups. This requires energy and time.

Many professional espresso machine machines utilize a vibration or rotary pump, which is a vibration model that uses a vibrating disc to generate the pressure and rotating models that push hot water through the grounds under high speed. Both types of machines can make a great espresso, but the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to an optimal temperature to extract. The steam created will eventually reach the portafilter, espressomachines which holds the espresso grounds. The steam is then channeled into the cup. The steam creates enough pressure to push the grounds of coffee through. This creates a foam on the top of the espresso. This is a sign of a good espresso.

There are three types of espresso machines, each with different pumps and brew temperature. There are many ways to control the brew as well as the size of cup that can be produced by the machine.

The earliest espresso machines were steam type. The first espresso machines were steam-type machines. The coffee tasted bitter and burned. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

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

The Filter

Typically, espresso machines use filters to separate the coffee grounds as they pass through the hot water. The filter is also a vital component of the machine's temperature control, as it helps prevent overheating.

A filter can also help with flavor because it allows for espressomachines a longer flowering period. This helps the beans release their nuances and gives an opportunity for better extraction.

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

It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you put the portafilter, the device which you put the coffee grounds into, when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds at a high pressure. These kinds of machines are usually less expensive and easier to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing as they only 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 been gaining popularity. They use an air compressor to push the hot water through the grounds and are much more portable than steam-driven electric machines.