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This Is The Ugly The Truth About Machine Espresso
How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the coffee we love. How exactly does it work?

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

The Group Head

The group head is the portafilter you insert when brewing espresso. It disperses water in the portafilter and regulates the pressure of the extraction. There are many different types of group heads, each with its own advantages and disadvantages. Some focus on temperature stability, some on pre-infusion capabilities, and still others are designed to control the lever. Some have a combination, such as the E61. This is a popular choice among baristas because it offers multiple advantages in a single package.

As you can see in the above image The group head features several notches to place your portafilter before twisting it with your hands to lock it in. There is also a gasket made of rubber that is a part of the notches and helps to create the seal when you insert your portafilter into the machine. The notches allow for precise placement of your portafilter. This is vital for an even extraction.

In addition to allowing you easily connect your portafilter, the group head is responsible for maintaining an even temperature. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is always at the right level for extraction. It is important to remember that even a small deviation can make the difference between a good and great espresso.

espresso machines uk that are used in espresso machines that rotate provide the nine atmospheric bar pressure that is required to extract espresso. This differs from manual piston machines that rely on a lever. The pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger before it is shot through the ground coffee inside the group head.

Pumps are generally less expensive and last longer than piston-driven machines. However, both types of machines may degrade due to overuse and inadequate cleaning. They also increase the complexity of mechanical systems which can result in the cost of even the simplest models.

Certain espresso machines can eliminate the pump completely and make use of steam pressure to make espresso. This can cause over-extraction because the boiler that produces steam also warms the water to boil. Additionally the machines often have to restore their pressure between cups, which requires time and energy.


Many espresso machines employ the rotary or vibration pump, with a vibration model using a vibrating disc to create pressure, and the rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, but rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler is the element that heats the water to the optimal temperature to extract. The steam that is produced is then directed to the portafilter, which holds the espresso grounds. The steam is then channeled into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This creates a foam on top of the espresso. This is one of the hallmarks of a great espresso.

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

The first espresso machines were steam-type. They employed one boiler to create both steam and brew however, the pressure they could produce was not very high - two bars of atmospheric pressure at most. This led to the coffee tasting burnt and bitter. The modern espresso machine was designed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso maker is a semiautomatic machine with an electric pump. These are the images people have when they imagine an espresso machine. If you have a semi-automatic machine you have to grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a great compromise between the human touch and mechanized quality.

The Filter

Espresso machines usually use a filter that separates the grounds of coffee from hot water. The filter is also an essential part of the machine's temperature control, since it stops overheating.

Filters also aid in flavor as it allows for a longer flowering period. This helps the beans to release their flavor and gives an opportunity for better extraction.

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

It's in this area that the magic happens. This is what makes espresso taste so good. The grouphead, often called the brew head, is the place where the portafilter (the device you put the coffee grounds into) sits when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to produce steam, which then pushes the hot water through the grounds at high pressure. These kinds of machines are usually less expensive and simpler to maintain than pump-driven models. They are however limited to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air-pump-driven espresso machines have been gaining popularity. They utilize an air compressor to force hot water through the grounds and are more portable than electric steam-driven machines.