How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How exactly does it work?

To make espresso machine with grinder hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Head of the Group

The group head is the portafilter you put in when making espresso. It distributes water into the portafilter, and controls the pressure of the extraction. There are numerous kinds of group heads each with their own advantages and drawbacks. Some are designed for the stability of temperature while some are designed to handle pre-infusion. Some are designed to control the lever. There are also some that have a combination of features, like the E61 one, which is the most popular choice among baristas for its ability to offer multiple perks in one package.

As you can see in the image above the head of the group is fitted with several notches. You can place your portafilter into these notches and twist the head to lock it. A gasket made of rubber is placed in the notches to create a seal as you insert your portafilter. The notches on the head allow for an exact position of the portafilter which is crucial to ensure an efficient extraction.

The group head not only lets you to place your portafilter easily but also maintains an even temperature. It does this by circulating hot water through the brew basket and around the portafilter, making sure that it is always at the correct temperature to extract. It is important to note that even a small espresso machine deviation can make the difference between a good and a great espresso.

The Pump

Contrary to manual piston machines which use a lever to pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure required to extract espresso. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally less expensive than piston-driven machines, and tend to last longer. However, both types of machine can be damaged by excessive use and inadequate cleaning. They also make mechanically complex, which can result in an expensive price for even the most basic models.

Some espresso machines can eliminate the pump entirely and use steam pressure to brew espresso. This could lead to over-extraction since the boiler that makes steam also heats the water to boil. In addition these machines typically have to rebuild their pressure between cups, which takes time and energy.

A majority of espresso machines utilize a rotary or vibration pump. A vibration model utilizes a vibrating disk to generate pressure, whereas the circular model pushes hot liquid through the ground at a high speed. Both machines produce great small espresso machine but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is the component that heats the water to the ideal temperature to extract. The resulting steam reaches the portafilter that contains ground espresso beans and is then pumped into the cup. During this process, the steam causes pressure to push through the coffee grounds. This produces a layer of crema that is then poured over. This is a hallmark of a good espresso.

There are three types of espresso machines, each with distinct pumps and brew temperature. There are different ways to control the amount of brew, as well as the size of cup that can be produced by the machine.

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

The most popular espresso maker is a semiautomatic machine with an electric pump. This is what people envision when they think of an espresso maker. If you have a semi-automatic machine you need to grind the beans and tamp them by hand. However, the pump controls the flow of water and pressure. This is a perfect compromise between human control and mechanised reliability.

The Filter

Typically, espresso machines employ filters to separate the coffee grounds as they pass through the hot water. The filter is also an essential component of the machine's temp control, since it helps to prevent overheating.

It also enhances flavor, as it allows for a more prolonged bloom phase. This helps the beans release their flavor and gives an opportunity to improve extraction.

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

This is where the magic happens, it's what makes espresso taste good. The grouphead, often called the brew head, is the place where the portafilter (the thing you put the ground coffee in) sits when you're making espresso.

In an espresso machines for home machine that is driven by steam, hot water is heated in an airtight container to produce steam, which is then pushed through the grounds under high pressure. These machines are cheaper and easier to maintain than pumps-driven models. They are however limited to create the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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