How Does Machine Espresso Work?

The machine espresso uses precise pressure, as well as a filtering technology that is amazing to make the coffee you enjoy. What exactly does it work?

In order to make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee, but the key difference is in the pressure.

The Head of the Group

As the name implies the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure that results from the extraction. There are a variety of types of group heads each with its distinct advantages and drawbacks. Some are focused on temperature stability, others on pre-infusion options, and others are designed to control the lever. There are also some that have a combination of features, such as the E61, which is the classic choice among many baristas for its ability to offer multiple perks in one package.

As you can see from the photo above the head of the group is fitted with several notches. The portafilter is placed inside these notches, and then twist the head to secure it. A gasket of rubber is situated in the notches to create a seal as you insert your portafilter. The notches on the head permit a precise location of the portafilter which is necessary for an even extraction.

Apart from allowing you easily place your portafilter in, the group head is also responsible for espresso machines maintaining a consistent temperature. It does this by circulating hot water through the brew basket and around the portafilter, making sure that it is always at the right temperature to extract. It is important to note that even a small difference can make the difference between a great 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 differs from manual piston machines that use a lever. The pressure builds by drawing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both types of machines are susceptible to degrading due to overuse and inadequate cleaning. Pumps are also more complicated mechanically, which can raise the cost of even the simplest models.

Some professional espresso machine machines make use of steam pressure instead of a pump in order to brew espresso. The drawback is that the same boiler that produces steam also raises the temperature of the water to the point of boiling and can result in excessive extraction. The machines must also continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines use either a vibration or rotary pump. A vibration model uses a vibrating disk to generate pressure, while a rotary model pushes hot water through the ground at a rapid speed. Both machines can make excellent espresso, however rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the part that heats water to the optimal temperature for extraction. The steam that is produced reaches the portafilter which holds ground espresso beans and is then pumped down into the cup. The steam is able to create enough pressure to push the grounds of coffee through. This results in a whipped-up top of the espresso. This is a sign of a good espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and how hot the brew is. There are a variety of ways to control the brew as well as the size of the cup that can be made by the machine.

The first espresso machines espresso machines were steam-based. The earliest espresso machines were steam types. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans yourself The pump, however, regulates the water flow and pressure. This is a great compromise between the human touch and the mechanised quality.

The Filter

Espresso machines typically use a filter that separates the grounds of coffee from hot water. The filter is also a vital component of the machine's temperature control, since it stops overheating.

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

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

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

In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam, which then pushes the hot water through the grounds with high pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. However, they are limited in their capacity to create the ideal conditions for brewing since they are only operating at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bar.

In recent years, compressed air-driven espresso machines have become more popular. They use an air compressor to push hot water into the grounds and are significantly more portable than electric steam-driven machines.