How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to create the perfect cup of coffee. How exactly does it work?

Espresso is produced by pushing hot water at high pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the primary difference.

The Head of the Group

The group head is the portafilter that you insert when brewing espresso. It disperses water in the portafilter, and then regulates the pressure of extraction. There are various kinds of group heads, each with their unique advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. There are also some that contain a variety of features, like the E61, which is the standard choice for many baristas for its ability to provide multiple benefits in a single package.

As you can see in the photo above the group head comes with several notches to place your portafilter and twist it by hand to lock it in. A gasket made of rubber is positioned inside the notches to help create a seal as you insert your portafilter. The notches allow for an exact placement of the portafilter. This is essential for an efficient extraction.

The group head not only lets you to insert your portafilter easily, but it also maintains a constant 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 to extract the coffee. This is important because even a small difference in temperature can mean the difference between excellent and great espresso.

The Pump

The motorized pumps used in espresso machines that rotate provide the nine atmospheric bars of pressure required to extract espresso. This is different from manually operated piston machines that employ levers. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be more affordable and last longer than piston-driven machines. However, both kinds of machines can deteriorate because of frequent use and inadequate cleaning. Pumps are also more complex mechanically, which can raise prices of even most basic models.

Some espresso machines do away with the pump completely and make use of steam pressure to make espresso. The drawback is that the same boiler that produces steam also raises the temperature of water to boiling which could lead to excessive extraction. In addition the machines often have to rebuild 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 the pressure, and a rotary model pushing hot water through the grounds under high speed. Both machines produce great espresso however rotary machines tend to be quieter, more durable and less likely to break down.

The Boiler

The boiler is the component that heats water to the ideal temperature for extraction. The steam that is produced reaches the portafilter, which is a container for espresso grounds. It is then funneled into the cup. The steam causes pressure to push through the coffee grounds. This creates a layer crema on top. This is one of the hallmarks of a great espresso.

There are three types of espresso machines espresso machines, each having different pumps and brew temperature. There are also different ways in which the brew could be controlled, as well as the size of the cup that the maker can create.

The earliest espresso machines were steam type. They had a single boiler to make both brew and steam, however the pressure they were able to create was minimal – two bars of atmospheric pressure at most. This resulted in the coffee tasting burnt and bitter. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most popular espresso machine is a semiautomatic model with an electric pump. These are what people imagine when they think of an espresso machine. With a semi-automatic espresso machine [site], you grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is an excellent compromise between human touch and the mechanized quality espresso machine.

The Filter

best espresso machine machines usually use a filter that separates the coffee grounds from the hot water. The filter is also an essential part of the temperature control system since it helps prevent the machine from overheating.

It also enhances flavor, since a filter can allow for a longer bloom phase. This lets the beans release their flavors, and allows for a better extraction.

It is important to keep in mind that even the finest filter can result in a bad cup of coffee. The quality of the beans and the extraction process, remain crucial.

It’s here that the magic happens. This is what makes espresso taste so good. The grouphead (also called the brewhead) is where you place the portafilter – the thingy used to place the grounds of coffee into when making professional espresso maker.

Steam-driven espresso machines use hot water heated in an airtight vessel to create steam. The steam then pushes hot water through the grounds of coffee under high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are limited in their ability bean to cup espresso machine create the perfect brewing conditions as they only operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.

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