How Does Machine Espresso Work?

Machine espresso employs precise pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly is it?

To make espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.

The Group Head

As the name implies the group head is where you put your portafilter in when brewing espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are many different types of group heads each with distinct advantages and disadvantages. Some are designed for stability in temperature, while others are built to handle pre-infusion. Others are built to control the lever. There are even some that contain a variety of features, such as the E61, which is considered the standard choice for many baristas for its ability to provide multiple benefits in one package.

As you can see in the above image the group head comes with several notches where you put your portafilter, then twist it with your hands to secure it. A gasket made of rubber is placed in the notches to create a seal when you insert your portafilter. The notches on the head permit an exact positioning of the portafilter which is crucial to ensure a consistent extraction.

The group head not only lets you to insert your portafilter easily however, it also keeps an even temperature. It does this by cycling hot water through the brew basket, 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 excellent espresso.

The Pump

The motorized pumps that are used in rotary espresso machines supply the nine atmospheric bar pressure required for espresso extraction. This differs from manual piston machines that rely on a lever. 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 models, and they tend to last longer, although both types of machine can get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, and can add to prices of even most basic models.

Some espresso machines use steam pressure instead of a pump to brew espresso. The downside is that the boiler that produces steam also raises the temperature of water until it reaches boiling and can result in excessive extraction. Additionally these machines are often required to rebuild their pressure between cups, which takes time and energy.

Many espresso machines employ the rotary or vibration pump, which has a vibration model that uses a vibrating disc to create the pressure and rotating models that push hot water through the grounds at high speed. Both machines can make excellent espresso but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the one that is used to heat the water to the perfect temperature to extract. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee and is then funneled down into the cup. During this process, steam creates pressure and pushes through the coffee grounds. This creates a crema on top of the espresso. This is one of the hallmarks of a good espresso.

There are three types of espresso machines, each with different pumps and the temperature of the brew. There are different ways that the brew can be controlled as well as the size of the cup the machine is capable of making.

The first espresso machines were steam type. The first espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semiautomatic machine with an electric pump. These are what people imagine when they imagine an espresso machine. With a semi-automatic espresso machine, you grind the beans and then tamp them by hand. The pump regulates the flow of water and pressure. This is a perfect combination of human control and mechanized reliability.

The Filter

Espresso machines typically use a filter that separates the grounds of coffee from hot water. The filter is also a vital part of the machine's temperature control, since it helps to prevent overheating.

It also helps with flavor, since a filter allows for a longer bloom phase. This lets the beans release their flavor and allows for better extraction.

However it is crucial to remember that even a good filter can make a terrible cup of coffee, since the quality of the beans and machine Espresso extraction is still crucial.

It's in this area that the magic takes place. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you put the portafilter - the thingy used to place the coffee grounds in, when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight container to create steam, which then pushes the hot water through the grounds under high pressure. These machines are cheaper and easier for the user 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 times, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor machine espresso to push hot water across the ground and are much more mobile than electric espresso maker steam-driven uk espresso machine machines.