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How Does Machine Espresso Work?

Machine espresso coffee machines uses precision pressure and amazing filter technology to make the perfect cup of coffee. What exactly is it?

Espresso is created by forcing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However the pressure is the main difference.

The Head of the Group

As the name implies, the group head is where you place your portafilter when brewing espresso. It disperses water into the portafilter, and regulates the pressure during the extraction. There are many different types of group heads each with their own advantages and drawbacks. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Some are designed to control the lever. There are even some that contain a variety of features, such as the E61 that is the classic choice among many baristas due to its ability to offer multiple perks in a single package.

As you can see in the above image the group head comes with several notches to place your portafilter and then twist it with your hands to secure it. A gasket made of rubber is positioned inside the notches, which helps create a seal as you insert your portafilter. The notches on the head allow for an exact location of the portafilter which is essential to ensure an efficient extraction.

Aside from allowing you to easily insert your portafilter, the group head is also responsible for maintaining an even temperature. It does this by circulating hot water through the brew container and around the portafilter to ensure that it's always at the right temperature for extraction. It is important to remember that even a few degree differences can make the distinction between a decent and a great espresso.

The Pump

Unlike manual piston machines, that use a lever to pressurize water, Rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure needed to extract espresso. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer. However, both types of machine can be damaged by excessive use and inadequate cleaning. They also make mechanically complex and can lead to costly prices for even the simplest models.

Some espresso machines can eliminate the pump entirely and utilize steam pressure to make espresso. This could lead to over-extraction since the boiler that makes steam also warms the water to boil. They also have to constantly rebuild their pressure in between cups. This requires energy and time.

A majority of espresso machines use a vibration or rotary pump, with a vibration model that uses a vibrating disc to generate the pressure, and the rotary model pushing hot water through the grounds at high speed. Both types of machine can produce an excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the element that heats water to the optimal temperature for extraction. The resultant steam then reaches the portafilter, which contains ground espresso beans and is then pumped down into the cup. The steam creates enough pressure to push the grounds of coffee through. This results in a layer crema on top. This is a hallmark of a good espresso.

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

The first espresso machines were steam types. They had a single boiler to make both steam and brew, however the pressure they were able to produce was not very high - two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most well-known espresso coffee machine maker is a semi-automatic one with an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the flow of water and pressure. This is a perfect combination of human control and mechanised accuracy.

The Filter

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

It also improves flavor, as it can allow for a longer bloom phase. This lets the beans release their flavor and also allows for better extraction.

However, it is important to keep in mind that even a top filter can make a terrible cup of coffee as the quality of the beans and extraction is still important.

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

Steam-driven espresso machines make use of hot water that is heated in an airtight container to produce steam. The steam then pushes hot water through coffee grounds under high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are limited in their capacity to create the perfect brewing conditions as they only operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air-pump-driven espresso machines have been gaining popularity. They use an air compressor to push hot water through the ground, and are more mobile than electric steam-driven espresso maker for home (just click the following document) machines.