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How Does Machine Espresso Work?

The machine espresso utilizes precision pressure, and filtering system that is awe-inspiring to make the coffee you enjoy. What 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, but the difference is in the pressure.

The Group Head

The name implies the group head is the place you place your portafilter while brewing espresso. It is responsible for dispersing water into the portafilter and controlling the pressure that results from the extraction. There are several different types of group head each with its own advantages and drawbacks. Some are specifically designed for temperature stability while others are built to handle pre-infusion. Others are made to control the lever. Some are a combination, such as the E61. This is a preferred choice for baristas because it offers multiple benefits in a single package.

As you can see in the above photo the group head is made up of many notches in which you can place your portafilter before twisting it with your hands to lock it in. There is also a gasket of rubber in the notches, which helps create the seal when you insert your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is essential for a consistent extraction.

In addition to allowing you to easily insert your portafilter, the group head is also responsible for maintaining an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant to extract the coffee. It is crucial to keep in mind that even a tiny differences can make the distinction between a great and a excellent espresso.

The Pump

The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bar pressure that is required to extract espresso. This differs from manual piston machines that rely on levers. This pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior to it is shot through the ground coffee in the group head.

Pumps tend to be less expensive than piston-driven machines, and tend to last longer, however both types of machine can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which can raise the price of even the most basic models.

Some espresso machines make use of steam pressure instead of a pump in order to brew espresso. This can cause over-extraction because the boiler that produces steam also heats the water until it comes to a boil. In addition these machines are often required to rebuild their pressure between cups, which requires time and energy.

Many espresso machines make use of the rotary or vibration pump, with a vibrating model using a rotating disc to create pressure, and rotating models that push hot water through the grounds at high end espresso machine speed. Both models can make excellent espresso, but Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the one that is used to heat the water to the right temperature to extract. The steam that is created gets to the portafilter which contains the espresso coffee grounds. It is then poured into the cup. During this process the steam creates enough pressure to push the grounds of coffee through. This produces a layer of crema that is then poured over. This is the hallmark of a good espresso.

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

The first espresso machines were steam-type. The earliest best espresso machine under 200 machines were steam-type machines. This led to the coffee tasting burnt and bitter. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most popular espresso maker is a semi-automatic machine that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans on your own The pump, however, regulates the flow of water and pressure. This is an excellent compromise between human touch and the mechanised accuracy.

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 part of the machine's temperature control, as it prevents overheating.

A filter also improves flavor since it allows for an extended flowering time. 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 make a bad cup of coffee. The quality of the beans and the extraction, are still crucial.

It's in this area that the magic happens. This is the reason why espresso tastes so good. The grouphead (also known as the brewhead) is where you place the portafilter - the thingy which you put the grounds of your coffee into when making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to produce steam, which then pushes the hot water through the grounds at high pressure. These types of machines are generally less expensive and simpler to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the ideal conditions for brewing since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.

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