How To Explain Machine Espresso To A Five-Year-Old

How Does Machine Espresso Work?

Machine espresso uses precision pressure and incredible filter technology to produce the perfect cup of coffee. How exactly does it work?

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

The Group Head

As the name suggests the group head is the place you put your portafilter in when making espresso. It distributes water into the portafilter and regulates the pressure of extraction. There are numerous kinds of group heads each with distinct advantages and drawbacks. Some are focused on temperature stability, others on pre-infusion features, and others are designed to control the lever. Some are a combination, like the E61. This is a popular choice among baristas because it offers multiple benefits in a single package.

As you can see in the above photo the group head comes with several notches to put your portafilter, then twist it manually to secure it. There is also a gasket of rubber that is a part of the notches and helps to create an airtight seal when you insert your portafilter into the machine. The notches permit an exact placement of the portafilter. This is essential for a consistent extraction.

The group head is not just able to allow you to put in your portafilter easily, but it also maintains an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter, making sure that it's always at the right temperature for extraction. This is important, as just a few degrees could be the difference between a good and excellent espresso.

The Pump

The motorized pumps used in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This is different from manual piston machines that use a lever. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven machines espresso machines, and they tend to last longer, however both types of machines could get damaged through overuse and lack of cleaning. They also make mechanically complex that can lead to a high price tag on even the simplest models.

Certain espresso machines utilize steam pressure instead of a pump for brewing espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of the water to the point of boiling which could lead to excessive extraction. Additionally these machines are often required to rebuild their pressure between cups, which requires time and energy.

Many espresso machines employ an rotary or vibrating pump, which is a vibration model using a vibrating disc to generate the pressure and the rotary model pushing hot water through the grounds under high speed. Both machines can make great espresso but rotary machines are quieter, more durable and less likely to break down.

The Boiler

The boiler is the part that heats the water to the ideal temperature for extraction. The resulting steam reaches the portafilter, which contains the ground espresso coffee and is then pumped into the cup. The steam causes enough pressure to push the grounds of coffee through. This results in a crema on top of the espresso. This is one of the hallmarks of a good espresso.

There are three types of espresso makers, which differ in the type of pump they employ and how hot the espresso machine black friday is. There are many ways to control the amount of brew, as well as the size of cup that can be produced by the machine.

The first espresso machines were steam types. They utilized one boiler to make both steam and brew, but the pressure they could produce was very low - just two bars of atmospheric pressure at most. The coffee tasted bitter and burnt. The modern retro espresso maker machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso maker is a semiautomatic machine with an electric pump. When people think of best small espresso machine machines, they think of these machines. With a semi-automatic espresso machine, you must grind the beans and then tamp them yourself but the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and mechanized consistency.

The Filter

Typically, espresso machines employ a filter to separate out the coffee grounds as they pass through the hot water. The filter is also an essential part of the machine's temperature control, as it prevents overheating.

It also enhances flavor, as a filter allows for a longer bloom time. This allows the beans to let their nuances out, and improves extraction.

It is important to remember that even the finest 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 good. The grouphead (also known as the brewhead) is where you place the portafilter - the thingy that you use to put the coffee grounds in, when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. This then pushes the hot water through the grounds under high pressure. These kinds of machines are typically cheaper and easier to maintain than pump-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, compressed air-pump-driven espresso machines have been gaining popularity. They utilize an air compressor to push the hot water through the grounds and are significantly more portable than steam-driven electric machines.