How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to make the perfect cup of coffee. What exactly is it?

Espresso is produced by pushing hot water under 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 coffee machine home. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are numerous kinds of group heads each with their own advantages and drawbacks. Some focus on temperature stability, some on pre-infusion features, and others are designed to control the lever. Some have a combination of features, such as the E61 one, which is the most popular choice among baristas due to its capacity to provide multiple benefits in one package.

As you can see in the above photo the group head is made up of several notches to put your portafilter, then twist it by hand to secure it. A gasket made of rubber is placed in the notches to make a seal when you insert your portafilter. The notches permit an exact placement of the portafilter. This is essential for a consistent extraction.

The group head not only lets you to insert your portafilter easily however it also keeps an even temperature. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it's always at the right temperature for extraction. This is important, as just a few degrees could mean the difference between good and great espresso.

The Pump

The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines that use levers. The pressure is built 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 machines could become damaged due to excessive use and poor cleaning. Pumps are also more complicated mechanically, which can raise the cost of even simplest models.

Certain italian espresso machine machines eliminate the pump completely and employ steam pressure to create espresso. This can cause over-extraction because the boiler that makes steam also heats the water to boil. In addition, these machines frequently have to restore their pressure between cups, which requires time and energy.

Many buy espresso machines machines make use of a vibration or rotary pump, which is a vibration model using a rotating disc to generate the pressure, and a rotary model pushing hot water through the grounds at high speed. Both models can make excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is what will heat the water to a temperature that is ideal for extraction. The steam that is produced will eventually reach the portafilter, which holds the espresso grounds. It is then poured into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This results in a whipped-up the top of the espresso. This is one of the main characteristics of a great espresso.

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

The first espresso machines were steam-type. They employed one boiler to make both steam and brew but the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This resulted in the coffee tasting burnt and bitter. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most popular espresso machine is a semiautomatic one with an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic espresso machine, you need to grind the beans and tamp them by hand. However, the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised accuracy.

The Filter

Espresso machines usually have a filter that separates the grounds of the coffee from the hot water. The filter is also a vital part of the machine's temperature control, since it helps to prevent overheating.

A filter also helps with flavor since it allows for the beans to flower for a longer period of time. This allows the beans to release their flavors, and improves extraction.

It is important to remember that even the best filter can make a bad cup of coffee. The quality of the beans and the extraction process are still very important.

It's in this area that the magic occurs. This is the reason why cheap Espresso machine tastes so good. The grouphead, sometimes referred to as the brew head, is where the portafilter (the container you place the coffee grounds into) sits when you're making espresso.

Steam-driven espresso machines use hot water that is heated in an airtight vessel to create steam. The steam then pushes hot water into the coffee grounds under high pressure. They are less expensive and easier to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal brewing conditions, 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 pump-driven espresso machines have been gaining popularity. They utilize an air compressor to push hot water into the grounds and are much more portable than steam-driven electric espresso maker machines.