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How Does Machine Espresso Work?

The machine espresso makes use of precision pressure, and a filtering system that is awe-inspiring to make the coffee for espresso machine you love. What exactly does it work?

Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to making drip coffee for espresso machine, but the major difference is in the pressure.

The Group Head

As the name implies, the group head is the place you put your portafilter in when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are a variety of types of group heads each with its unique advantages and drawbacks. Some are designed for temperature stability while others are built to handle pre-infusion. Some are designed to control the lever. There are even some that have a combination of features, like the E61 one, which is to be the most popular among baristas because of its ability to provide multiple benefits in a single package.

As you can see in the image above the head of the group is equipped with several notches. You place your portafilter into these notches and twist the head to lock it. A rubber gasket is located inside the notches to help create a seal when you insert your portafilter. The notches allow for precise placement of the portafilter. This is vital for an efficient extraction.

In addition to allowing you easily place your portafilter in, the group head is responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew basket and around the portafilter to ensure that it's always at the correct temperature for extraction. This is important because just a few degrees could make the difference between a excellent and great espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines that use a lever. The pressure is created by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven machines and tend to last longer, but both types of machines may degrade with overuse and insufficient cleaning. Pumps are also more complicated mechanically, and can add to the cost of even the simplest models.

Certain espresso machines utilize steam pressure instead of a pump to make espresso. The drawback is that the boiler that produces steam also raises the temperature of the water until it reaches boiling, which can lead to excessive extraction. The machines espresso must also constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines make use of an rotary or a vibration pump. A vibration model makes use of the vibrating disk to create pressure, while a rotary model pushes hot water through the ground at a fast speed. Both models can make a great espresso, but rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the one that will heat the water to the right temperature to extract. The steam produced gets to the portafilter which is a container for espresso machines for home grounds. The steam is then channeled into the cup. The steam creates pressure to push through the coffee grounds. This creates a layer crema that is then poured over. This is one of the main characteristics of a great espresso.

There are three different types of espresso machines, each with different types of pumps and the temperature of the brew. There are different ways to control the strength of the brew and the size of cup that can be made by the machine.

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

The most common espresso machine is a semiautomatic that has an electric pump. These are what people imagine when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

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

A filter also helps with flavor, as it permits a longer flowering phase. This helps the beans let their nuances out and provides an opportunity for a better extraction.

It is important to keep in mind that even the best filter could result in a poor cup of coffee. The quality of the beans, as well as the extraction, remain vital.

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

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to create steam. The steam then pushes hot water through grounds of the coffee under pressure. These kinds of machines are generally less expensive and simpler to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing as they only 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 use an air compressor to push hot water across the ground, and are more mobile than steam-driven electric espresso machines.