How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it that makes it work?

To make 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 water into the portafilter and controlling the pressure of the resulting extraction. There are several different types of group heads, each with their unique advantages and disadvantages. Some are specifically designed for temperature stability while others are built to handle pre-infusion. Others are made to control the lever. Some come with a combination of both, like the E61. This is a favorite among baristas because it offers multiple benefits in a single package.

As you can see in the above photo, the group head has several notches to place your portafilter and then twist it manually to lock it in. A rubber gasket is located in the notches to make a seal when you insert your portafilter. The notches on the head permit a precise location of the portafilter which is vital to ensure an even extraction.

The group head is not just able to allow the portafilter to be inserted easily but also maintains an even temperature. It does this by circulating hot water through the brew pan and around the portafilter, ensuring that it is always at the correct temperature to extract. This is important, as even a few degrees can be the difference between a good and great espresso.

The Pump

Unlike manual piston machines, which rely on a lever that pressurize water, Rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure necessary to extract espresso. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer, but both types of machines could degrade with overuse and insufficient cleaning. Pumps are also more complex mechanically, which can increase prices of even simple models.

Some espresso machine black friday machines employ steam pressure instead of a pump for brewing espresso. This can result in over-extraction because the boiler that produces steam also causes the water to boil. The machines also need to continually rebuild their pressure between cups. This takes energy and time.

A majority of retro espresso maker machines use a vibration or rotary pump, which has a vibration model using a rotating disc to create the pressure and a rotary model pushing hot water through the grounds at high speed. Both machines can produce excellent espresso, however rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is the component that heats water to the ideal temperature to extract. The steam produced reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then poured into the cup. The steam creates enough pressure to push the grounds of coffee through. This creates a layer crema that is then poured over. This is one of the hallmarks of a great espresso.

There are three kinds of espresso makers, and they differ in the type of pump they employ and how hot the espresso is. There are different ways to control the brew and the size of the cup that can be produced by the machine.

The first espresso machines were steam-types. The earliest espresso machines were steam-type machines espresso. The coffee tasted bitter and burned. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most commonly used espresso maker is a semi-automatic one that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans on your own The pump, however, regulates the water flow and pressure. This is a great compromise between the human touch and the mechanised quality.

The Filter

Typically, espresso machines utilize filters that separate the grounds of the coffee as they go through the hot water. The filter is also an essential element of the temperature control system, as it keeps the machine from overheating.

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

However, it is important to keep in mind that even a good filter can result in a poor cup of coffee, because the quality of the beans and extraction is still crucial.

This is where the magic happens, it's the thing that makes an best budget espresso machine really taste great. The grouphead (also called the brewhead) is where you place the portafilter, the device that you use to put the coffee grounds in, while making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds with high pressure. These kinds of machines are usually cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to provide the perfect brewing conditions because they operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bar.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They utilize an air compressor to push the hot water through the grounds and are significantly more portable than steam-driven electric machines.