How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the coffee we love. But 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 pressure is the main difference.

The Group Head

As the name suggests the group head is where you place your portafilter while making espresso. It disperses water in the portafilter and regulates the pressure of the extraction. There are many different types of group heads each with their own advantages and drawbacks. Some are designed to provide the stability of temperature while some are specifically designed to handle pre-infusion. Others are built to control the lever. Some have a combination, such as the E61. This is a very popular choice for baristas since it provides multiple benefits in a single package.

As you can see in the photo above the group head is made up of numerous notches that you can place your portafilter before twisting it with your hands to secure it. A rubber gasket is located in the notches to create a seal as you insert your portafilter. The notches permit precise placement of your portafilter. This is crucial to ensure an accurate extraction.

The group head not only allows the portafilter to be inserted easily however it also keeps the temperature at a constant level. This is accomplished by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is always at the right level for extraction. This is important, as even a few degrees can mean the difference between excellent and great espresso.

The Pump

Motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure required to extract espresso. This is different from manual piston machines espresso which use a lever. The pressure is created by removing tap water from a reservoir, and pumping it through a heat exchanger prior it is shot through the ground coffee in the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to excessive use and poor cleaning. They also make mechanically complex which can result in a high price tag on even the simplest models.

Some espresso machines eliminate the pump completely and use steam pressure to brew espresso. The drawback is that the boiler that produces steam also increases the temperature of water to the point of boiling and can result in excessive extraction. In addition, these machines frequently have to restore their pressure between cups, which takes time and energy.

Many espresso machines utilize an rotary or vibrating pump, which is a vibration model using a vibrating disc that generates the pressure and the rotary model pushing hot water through the grounds at high end espresso machine speed. Both machines can produce excellent espresso, however rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler is the component that heats water to an ideal temperature to extract. The steam that is produced reaches the portafilter which holds the ground espresso coffee, and is then pumped down into the cup. During this process the steam generates enough pressure to push the grounds of coffee through. This results in a whipped-up top of the espresso and filter coffee machine. This is one of the main characteristics of a great espresso.

There are three different types of espresso machines, each having different types of pumps and the temperature of the brew. There are also different ways in which the brew could be controlled and the dimensions of the cup the machine is capable of making.

The first espresso machines were steam-type. The first espresso machines were steam-type machines. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso machine is a semiautomatic one with an electric pump. These are what people imagine when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans yourself The pump, however, regulates the water flow and pressure. This is an excellent solution that combines human control with mechanized consistency.

The Filter

Espresso machines typically have a filter that separates the grounds of the coffee from hot water. The filter is also a vital element of the temperature control system since it helps prevent the machine from overheating.

A filter also improves flavor because it allows for an extended flowering time. This lets the beans let their nuances out, and also allows for better extraction.

It is important to keep in mind that even the best small espresso machine filter can result in a bad cup of coffee. The quality of the beans, and the extraction process, are still crucial.

This is where the magic happens, it's what makes buy espresso machine taste good. The grouphead, sometimes called the brew head, is where the portafilter (the device you put the ground coffee in) is placed when you're making espresso.

Steam-driven espresso machines use hot water heated in an airtight container to make steam. The steam then moves hot water through the grounds of the coffee under pressure. These kinds of machines tend to be less expensive and easier to maintain than pump-driven models. However, they are limited in their ability to create the ideal conditions for brewing 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 force hot water through the grounds and Machine Espresso are more portable than steam-driven electric machines.