10 Machine Espresso Meetups You Should Attend

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and mind-blowing filter technology to create the perfect cup of coffee. How exactly does it work?

Espresso is created by forcing hot water at high pressure through finely ground coffee. The process is similar to making drip coffee however the main difference lies in the pressure.

The Head of the Group

The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure that results from the extraction. There are various kinds of group head each with its particular advantages and disadvantages. Some are focused on temperature stability, some on pre-infusion features, and others are designed to control the lever. Some come with a combination of both, like the E61. This is a very popular choice for baristas as it provides a variety of benefits in one package.

As you can see in the image above the head of the group is fitted with several notches. You can place your portafilter inside these notches, and then twist the head to secure it. A rubber gasket is located inside the notches, which helps create a seal as you insert your portafilter. The notches permit the precise placement of the portafilter. This is crucial for an accurate extraction.

The group head does not just allow you to insert your portafilter easily however, it also keeps a constant temperature. It does this by cycling hot water through the brew pan and around the portafilter, ensuring that it's always at the correct temperature to extract. This is important, as just a few degrees could make the difference between a good and excellent espresso.

The Pump

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

Pumps tend to be less expensive than piston-driven machines, and they tend to last longer. However, both types of machines may be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, which could increase the cost of even simplest models.

Some best espresso machine Under 200 machines remove the pump completely and instead use steam pressure to brew 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 between cups. This requires energy and time.

Many espresso machines employ either a rotary or vibration pump, with a vibration model using a vibrating disc to create pressure and a rotary model pushing hot water through the grounds at high speed. Both types of machine can produce an excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler makes the water warm to a temperature that is ideal for extraction. The steam created is then directed to the portafilter, which contains the espresso coffee grounds. It is then poured into the cup. In this process, the steam creates pressure to push through the coffee grounds. This results in a layer of crema on top. This is the hallmark of a good espresso.

There are three kinds of espresso makers, and they differ in the kind of pump they use and how hot the espresso is. There are different ways that the brew can be controlled, as well as the size of the cup that the machine can produce.

The first espresso machines were steam-types. The earliest espresso machines were steam types. This led to the coffee tasting bitter and burnt. The modern espresso machine was invented by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they think of these machines. Semi-automatic machines require you to grind and tamp your beans yourself while the pump controls the flow of water and pressure. This is a great compromise between the human touch and mechanized quality.

The Filter

Typically, espresso machines employ filters that separate the coffee grounds as they pass through the hot water. The filter is also a crucial part of the temperature control system, as it keeps the machine from overheating.

A filter can also help with flavor as it allows for a longer flowering phase. This allows the beans to release their nuances, and improves extraction.

It is important to keep in mind that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction process, remain vital.

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 place the portafilter, which is the thingy used to place the coffee grounds in, while making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight vessel to create steam. The steam then pushes hot water through grounds of coffee under high pressure. These types of machines tend to be less expensive and simpler to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, espresso machines driven by a compressed air pump have become increasingly popular. They use an air compressor to force the hot water through the grounds and are significantly more portable than steam-driven electric machines.