Maisie Birdwood

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the delicious coffee we enjoy. But how exactly does it work?

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

The Group Head

The group head is the portafilter you put in when making espresso. It disperses the water into the portafilter, and regulates the pressure of the extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some are designed to provide temperature stability while others are designed to handle pre-infusion. Others are built to control the lever. Some include a combination like the E61. This is a preferred choice for baristas since it provides multiple advantages in one package.

As you can see in the photo above The group head features numerous notches that you can place your portafilter and twist it with your hands to lock it in. A gasket made of rubber is positioned inside the notches, which helps create a seal as you insert your portafilter. The notches permit an exact placement of the portafilter. This is crucial for an accurate extraction.

Apart from allowing you easily connect your portafilter, the group head is responsible to maintain an even temperature. This is done by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is constant for extraction. It is important to remember that even a tiny deviation can make the difference between a good and excellent espresso.

The Pump

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

Pumps are generally more affordable and last longer than piston-driven machines. However, both types of machines can degrade due to overuse and insufficient cleaning. They also add mechanical complexity and can lead to an expensive price for even the most basic models.

Some espresso machines can eliminate the pump entirely and employ steam pressure to create espresso. This can lead to over-extraction as the boiler that makes steam also causes the water to boil. These machines also have to continuously rebuild their pressure between cups. This requires energy and time.

Many espresso machines make use of an rotary or vibrating pump, which has a vibration model using a rotating disc to generate the pressure and an rotary model that pushes hot water through the grounds under high speed. Both machines produce great espresso, but rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler is the part which heats the water to the optimal temperature for extraction. The resulting steam reaches the portafilter which holds the ground best home espresso machine coffee and gets funnelled down into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a layer of crema that is then poured over. This is one of the hallmarks of a great Espresso Coffee Machine Uk.

There are three kinds of espresso makers, and they differ in the type of pump they use and how hot the coffee is. There are many ways to control the brew as well as the size of the cup that can be made by the machine.

The first espresso machines were steam-types. They used a single boiler to make both brew and steam, however the pressure they were able to generate was low - only two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. The modern espresso machine was invented by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic machine with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine you must grind the beans and then tamp them by hand. However, the pump controls the flow of water and pressure. This is an excellent compromise between human control and mechanized accuracy.

The Filter

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

It also helps with flavor, as it lets you enjoy a longer bloom phase. This helps the beans release their nuances and gives an opportunity for a better extraction.

However, it is important to remember that even a great filter can produce a bad cup of coffee, as the quality of the beans and extraction are essential.

This is where the magic happens, it's what makes an espresso really taste good. The grouphead, sometimes referred to as the brew head, is where the portafilter (the thingy you put the ground coffee and espresso machine in) sits when you're making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight vessel to create steam. The steam then moves hot water through the coffee grounds under high pressure. These machines are less expensive and easier to maintain than pumps-driven models. However, they are limited in their capacity to create the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bars.

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