How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and incredible filter technology to produce the delicious coffee we enjoy. What 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. However the pressure is the major difference.

The Group Head

As the name implies, the group head is where you put your portafilter in when making espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure that results from the extraction. There are numerous kinds of group heads, each with its own advantages and drawbacks. Some are specifically designed for stability of temperature while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are even some that have a combination of features, such as the E61, which is considered the standard choice for many baristas due to its ability to offer multiple benefits in one package.

As you can see in the image above the group head comes with numerous notches that you can place your portafilter and then twist it with your hands to secure it. There is also a gasket made from rubber that resides inside the notches, which helps create the seal when you insert your portafilter into the machine. The notches on the head allow for a precise position of the portafilter which is essential to ensure an efficient extraction.

Aside from allowing you to easily place your portafilter in, the group head is responsible for maintaining a consistent temperature. It does this by cycling hot water through the brew basket, and around the portafilter to ensure that it is always at the correct temperature for extraction. It is important to note that even a slight variation can mean the difference between a decent and a great espresso.

The Pump

The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bar pressure needed for espresso extraction. This differs from manually operated piston machines that employ a lever. The pressure is created 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 degrade because of excessive use and poor cleaning. Pumps are also more complicated mechanically, which can increase the cost of even simplest models.

Some retro espresso machine machines use steam pressure instead of a pump to brew espresso machine small. The downside is that the same boiler that produces steam also increases the temperature of water to boiling, which can lead to excessive extraction. Additionally these machines typically have to restore their pressure between cups, which takes time and energy.

A majority of espresso machines utilize a rotary or vibration pump. A vibration model utilizes the vibrating disk to create pressure, while a Rotary model pushes hot coffee through the ground at high speed. Both types of machines can produce an excellent espresso, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the component that heats the water to the optimal temperature for extraction. The resulting steam is then transferred to the portafilter that contains the ground espresso coffee, and is then pumped down into the cup. In this process, the steam creates pressure to push through the coffee grounds. This results in a whipped-up top of the espresso and filter coffee machine. This is a sign of a great espresso.

There are three kinds of espresso makers, which differ in the kind of pump they use and the degree of heat that the brew is. There are a variety of ways in which 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-based. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso machine is a semiautomatic one with an electric pump. These are what people imagine when they think of an espresso maker. With a semi-automatic machine you have to 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 touch and the mechanised consistency.

The Filter

Espresso machines typically have filters that separate the coffee grounds from the hot water. The filter is also an important element of the temperature control system as it prevents the machine from overheating.

It also helps with flavor, as a filter lets you enjoy a longer bloom time. This allows the beans to let their nuances out, and improves extraction.

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

It's here that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you place the portafilter - the thingy used to place the coffee grounds into, while making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. This is then pushed through the grounds at a high pressure. These kinds of machines are generally less expensive and easier to maintain than pump-driven models. They are however limited for creating the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machines driven by compressed air-pump have become increasingly popular. They utilize an air compressor to force hot water into the ground. They are also more mobile than electric steam-driven espresso machines.