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How To Explain Machine Espresso To Your Grandparents
How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the perfect cup of coffee. How exactly does it work?

In order to make 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 group head is the portafilter that you place in the espresso maker when making it. It disperses water into the portafilter, and regulates the pressure of the extraction. There are many different types of group heads, each with its own advantages and drawbacks. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are built to control the lever. Some come with a combination of both, 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 picture above the head of the group is fitted with several notches. The portafilter is placed in these notches and then twist the head to secure it. There is also a gasket of rubber that is a part of the notches, which helps create an airtight seal after inserting your portafilter into the machine. The notches permit the precise placement of the portafilter. This is crucial to ensure an efficient extraction.

The group head is not just able to allow you to place your portafilter easily however, it also keeps the temperature at a constant level. This is achieved by cycling hot water around the portafilter and through the brew-basket, ensuring that the temperature is at the right level for extraction. This is important because even a small difference in temperature can make the difference between a good and great espresso.

The Pump

Unlike manual piston machines, which use a lever to pressurize water, rotating espresso machines rely upon motorized pumps that provide the nine atmospheric bars of pressure necessary for espresso extraction. The pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger prior it is shot through the ground coffee inside the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading because of excessive use and inadequate cleaning. Pumps are also more complex mechanically, which could increase the cost of even simplest models.

Certain espresso machines can eliminate the pump completely and make use of steam pressure to make espresso. This can lead to over-extraction as the boiler that produces steam also heats the water to boil. Additionally, Coffeee have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines utilize either a rotary or vibration pump, with a vibration model using a vibrating disc that generates the pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines produce great espresso, but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the component which heats the water to the optimal temperature to extract. The resultant steam then reaches the portafilter that contains the ground espresso and is then pumped down into the cup. The steam generates enough pressure to push the coffee grounds through. This produces a layer of crema on top. This is one of the hallmarks of a good espresso.

There are three types of espresso makers, and they differ in the type of pump they use and how hot the espresso is. There are also different ways in which the brew can be controlled, as well as the dimensions of the cup the maker can create.


The earliest espresso machines were steam types. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. This is the reason Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most common espresso maker is a semi-automatic device with an electric pump. This is what people envision when they think of an espresso machine. With a semi-automatic espresso machine, you have to grind the beans and tamp them by hand. The pump is able to regulate the flow of water and pressure. This is an excellent combination of human control and mechanised accuracy.

The Filter

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

A filter also helps with flavor as it allows for a longer flowering phase. This lets the beans release their flavor and allows for better extraction.

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

It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead, also referred to as the brew head, is where the portafilter (the thing you put the coffee grounds into) is located when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to create steam. The steam then pushes hot water through grounds of coffee at high pressure. These kinds of machines are typically less expensive and simpler to maintain than pump-driven models. They are however limited to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machines powered by a compressed air compressor have become increasingly popular. They utilize an air compressor to force hot water into the ground. They are also more mobile than electric steam-driven espresso machines.

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