How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly does it work?

To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the major difference is in the pressure.

The Group Head

The group head is the portafilter you put in when making espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are several different types of group heads each with its own advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. Some come with a combination of both, like the E61. This is a popular choice among baristas because it offers multiple advantages in one package.

As you can see in the photo above the head of the group is fitted with several notches. It is possible to place your portafilter into these notches and twist the head to lock it. There is also a gasket made from rubber that resides inside the notches to help create a seal when you insert your portafilter into the machine. The notches on the head allow for an exact location of the portafilter which is necessary for an efficient extraction.

The group head not only lets the portafilter to be inserted easily however, it also keeps an even temperature. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it is always at the correct temperature for extraction. It is crucial to keep in mind that even a tiny variation can mean the difference between a good and a great best budget espresso machine.

The Pump

Contrary to manual piston machines that use a lever to pressurize water, rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure needed to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are generally less expensive than piston-driven models, and they tend to last longer, although both types of machines can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which can raise prices of even simplest models.

Certain best espresso machine uk machines utilize steam pressure instead of a pump in order to brew espresso. This can lead to over-extraction as the boiler that produces steam also heats the water to boil. The machines also need to constantly rebuild their pressure in between cups. This requires energy and time.

A majority of espresso machines use a vibration or rotary pump, which is a vibration model that uses a vibrating disc to create the pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines can produce excellent best small espresso machine, however rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is what heats the water to a temperature that is ideal to extract. The steam produced is then directed to the portafilter, which contains the espresso coffee grounds. It is then funneled into the cup. During this process, the steam creates pressure to push through the coffee grounds. This creates a foam on the top of the espresso. This is one of the main characteristics of a good espresso.

There are three kinds of espresso makers, which differ in the type of pump they use and how hot the coffee is. There are various ways in which the brew can be controlled, as well as the size of the cup the machine is capable of making.

The first espresso machines were steam type. They had one boiler to create both steam and brew but the pressure they could generate was low - only two bars of atmospheric pressure maximum. This led to the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine, you have to grind the beans and then tamp them yourself but the pump controls the flow of water and pressure. This is an excellent compromise between human control and mechanized accuracy.

The Filter

Espresso machines typically use filters that separate the coffee grounds from the hot water. The filter is also an essential component of the machine's temp control, since it stops overheating.

It also aids in flavor, since a filter can allow for a longer bloom time. This allows the beans to release their nuances and gives the chance for better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans, and the extraction process remain crucial.

This is where the magic happens. It's what makes espresso taste great. The grouphead (also called the brewhead) is where you place the portafilter, the thingy that you put the grounds of your coffee into when making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to produce steam, which then pushes the hot water through the grounds at a high pressure. These machines are less expensive 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, espresso machines driven by a compressed air compressor have become increasingly popular. They use an air compressor to force hot water into the ground. They are also more mobile than steam-driven electric espresso machines.