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 that makes 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 primary difference.

The Head of the Group

The group head is the portafilter that you place in the espresso maker when making it. It disperses water in the portafilter, and regulates the pressure of the extraction. There are a variety of types of group heads, machines espresso Machines each with their own advantages and disadvantages. Some focus on temperature stability, whereas others on pre-infusion features, and others are designed to control the lever. Some have a combination, such as the E61. This is a favorite among baristas because it offers multiple benefits in a single package.

As you can see in the image above, the group head has several notches to place your portafilter and twist it by hand to secure it. There is also a rubber gasket that is a part of the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches allow for precise placement of the portafilter. This is essential for an accurate extraction.

Aside from allowing you to easily insert your portafilter, the group head is also responsible to maintain an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter to ensure that it's always at the correct temperature to extract. This is vital, because even a few degrees can mean the difference between good and great espresso.

The Pump

The motorized pumps in espresso machines that rotate provide the nine atmospheric bar pressure required to extract espresso. This is different from manual piston machines which use a lever. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior to being pushed through the ground coffee inside the group head.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both types of machines can degrade due to excessive use and poor cleaning. They also increase the complexity of mechanical systems, which can result in costly prices for even the most basic models.

Some espresso machines espresso machines use steam pressure instead of a pump to brew espresso capsule machine. The drawback is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling which can cause excessive extraction. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines employ a vibration or rotary pump, which is a vibration model using a vibrating disc to create the pressure, and rotating models that push hot water through the grounds under high speed. Both models are capable of producing excellent espresso, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is used to heat the water to the right temperature to extract. The resulting steam reaches the portafilter containing the ground espresso coffee and is then funneled down into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This results in a layer crema on top. This is one of the main characteristics of a great espresso.

There are three types of espresso makers, and they differ in the type of pump they employ and how hot the coffee is. There are a variety of ways to control the brew and the size of the cup that can be produced by the machine.

The earliest espresso machines were steam-based. They used only one boiler to make both brew and steam, however the pressure they were able to generate was low - only two bars of atmospheric pressure at the most. The coffee tasted bitter and burned. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known espresso machine is a semiautomatic one with an electric pump. These are the things people think of when they think of an espresso maker. If you have a semi-automatic machine you must grind the beans and tamp them by hand. However, the pump regulates the flow of water and pressure. This is a great solution that combines human control with mechanised reliability.

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from the hot water. The filter is also a vital component of the machine's temp control, as it prevents overheating.

It also helps with flavor as a filter lets you enjoy a longer bloom phase. This helps the beans release their flavor and gives an opportunity to improve extraction.

It is important to remember that even the most efficient filter can result in a bad cup of coffee. The quality of the beans and the extraction, are still crucial.

This is where the magic happens. It's what makes espresso taste good. The grouphead (also called the brewhead) is where you place the portafilter, which is the thingy that you put the coffee grounds in, when making espresso.

Steam-driven espresso coffee machine for home machines use hot water heated in an airtight container to make steam. The steam then pushes hot water into the grounds of the coffee under pressure. These kinds of machines tend to be cheaper and easier to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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