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How Does Machine Espresso Work?

The machine espresso utilizes precision pressure, and filtering technology that is amazing to create the coffee you love. How exactly does it work?

Espresso is produced by pushing hot water under pressure through finely-ground coffee. The process is similar to making drip coffee. However the pressure is the major difference.

The Head of the Group

The group head is the portafilter that is inserted when you are making espresso. It distributes water into the portafilter, and regulates the pressure during the extraction. There are a variety of types of group head each with its own advantages and disadvantages. Some are designed to provide the stability of temperature while some are specifically designed to handle pre-infusion. Others are built to control the lever. Some are a combination, like the E61. This is a favorite among baristas because it offers multiple advantages in one package.

As you can see in the above image the group head is made up of many notches in which you can place your portafilter and then twist it with your hands to secure it. A gasket made of rubber is placed inside the notches to help create a seal while you insert your portafilter. The notches on the head allow for an exact position of the portafilter which is vital for a consistent extraction.

In addition to allowing you to easily place your portafilter in, the group head is also responsible for maintaining a consistent temperature. This is done by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is always at the right level for extraction. It is important to realize that even a tiny variation can mean the difference between a great and a excellent espresso.

The Pump

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

Pumps are typically cheaper and last longer than piston-driven machines. However, both kinds of machines can degrade due to overuse and insufficient cleaning. Pumps are also more complicated mechanically, which could increase the cost of even simple models.

Certain espresso machines do away with the pump completely and employ steam pressure to create espresso. The drawback of this is that the boiler that produces steam also increases the temperature of the water to boiling which could lead to over-extraction. In addition the machines often have to restore their pressure between cups, which takes time and energy.

Many espresso machines utilize either a rotary or vibration pump, which is a vibration model that uses a vibrating disc that generates the pressure, and the rotary model pushing hot water through the grounds at high end espresso machine speed. Both machines can produce excellent espresso however rotary machines tend to be quieter, more durable and less likely to break.

The Boiler

The boiler is the component which heats the water to the ideal temperature to extract. The resulting steam is then transferred to the portafilter, which contains ground espresso beans and gets funnelled down into the cup. During this process the steam causes enough pressure to push the grounds of the coffee through. This results in a layer crema on top. This is one of the main characteristics of a great home espresso machine.

There are three types of espresso makers, and they differ in the kind of pump they use and how hot the espresso is. There are a variety of ways that the brew can be controlled as well as the size of the cup the maker can create.

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

The most popular barista espresso coffee machine maker is a semi-automatic machine 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 while the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised quality.

The Filter

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

It also helps with flavor, as it lets you enjoy a longer bloom time. This allows the beans to let their nuances out, and allows for a better extraction.

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

This is where the magic happens, it's what makes an espresso really taste great. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy used to place the grounds of coffee into when making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight vessel to create steam. The steam then pushes hot water through the grounds of coffee under high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are not as efficient in their capacity to create the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, compressed air-driven espresso machines have been gaining popularity. They utilize an air compressor to force hot water into the grounds and are more portable than electric steam-driven machines.