How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the perfect cup of coffee. But how exactly does it work?

To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee however the main difference lies in the pressure.

The Head of the Group

The name implies the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure of the extraction. There are many different kinds of group head each with its particular 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. There are some that come with a range of features, like the E61, which is considered the most popular choice among baristas due to its capacity to offer multiple benefits in a single package.

As you can see in the photo above, the group head has many notches in which you can place your portafilter before twisting it manually to secure it. A rubber gasket is located inside the notches, which helps create a seal when you insert your portafilter. The notches on the head permit an exact positioning of the portafilter which is essential to ensure an efficient extraction.

In addition to allowing you to effortlessly insert your portafilter the group head is responsible to maintain an even temperature. It does this by circulating hot water through the brew basket, and around the portafilter, ensuring that it's always at the correct temperature to extract. It is crucial to keep in mind that even a slight variation can mean the difference between a good and great espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure that is required to extract espresso. This is different from manual piston machines that rely on a lever. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven models, and they tend to last longer. However, both types of machines may become damaged due to excessive use and poor cleaning. Pumps are also more complicated mechanically, and can add to prices of even simpler models.

Some best home espresso machine machines use steam pressure instead of a pump for brewing espresso. This can lead to over-extraction as the boiler that makes steam also causes the water to boil. The machines must also continuously rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines utilize a rotary or vibration pump. A vibration model utilizes a rotating disk to generate pressure, whereas the Rotary model pushes hot coffee through the ground at high speed. Both models can make a great espresso, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler heats the water to the right temperature for extraction. The resultant steam then reaches the portafilter containing the ground espresso coffee, and is then funneled down into the cup. The steam causes enough pressure to push the grounds of the coffee through. This creates a crema on the top of the espresso. This is a sign of a good espresso.

There are three kinds of espresso makers. They differ in the kind of pump they use and the degree of heat that the small espresso machine is. There are a variety of ways to control the amount of brew, as well as the size of the cup that can be made by the machine.

The first espresso machines were steam-type. The first espresso machines were steam types. The coffee tasted bitter and burned. This is why the Milanese makers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most common professional espresso machine for home maker is a semiautomatic machine with an electric pump. These are the images people have when they imagine an espresso machine. With a semi-automatic machine, you need to grind the beans and tamp them yourself but the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised quality.

The Filter

Espresso machines usually use a filter that separates the grounds of the coffee from the hot water. The filter is also an essential component of the machine's temp control, as it helps prevent overheating.

It also enhances flavor, since a filter lets you enjoy a longer bloom time. This helps the beans to let their nuances out and provides an opportunity for a better extraction.

However, it is important to keep in mind that even a good filter can result in a poor cup of coffee as the quality of the beans and extraction are vital.

This is where the magic happens, it's the thing that makes an espresso really taste good. The grouphead, also referred to as the brew head, is where the portafilter (the thing you put the coffee grounds into) is placed when making espresso.

Steam-driven espresso machine coffee machines make use of hot water heated in an airtight vessel to create steam. The steam then moves hot water through the coffee grounds under high pressure. These types of machines are typically cheaper and easier to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent times, home espresso machine machines powered by a compressed air compressor have become increasingly popular. They utilize an air compressor to push hot water through the ground. They are also more mobile than electric steam-driven espresso machines.