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How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to create the coffee we love. How does it work exactly?

In order to make commercial espresso machine hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However the pressure is the primary difference.

The Head of the Group

The group head is the portafilter that is inserted when you are making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the resulting extraction. There are a variety of types of group heads, each with their distinct advantages and drawbacks. Some are specifically designed for stability in temperature, while others are designed to handle pre-infusion. Others are made to control the lever. Some include a mix of features, such as the E61, which is considered the standard choice for many baristas due to its capacity to offer multiple perks in one package.

As you can see in the above photo the head of the group has a number of notches. The portafilter is placed into these notches and twist the head to secure it. A gasket made of rubber is placed inside the notches, which helps create a seal while you insert your portafilter. The notches on the head permit a precise position of the portafilter which is crucial to ensure an even extraction.

Aside from allowing you to easily place your portafilter in, the group head is also responsible for maintaining a consistent temperature. It does this by cycling hot water through the brew basket and around the portafilter, making sure that it is always at the correct temperature for extraction. This is vital, because even a best small espresso machine difference in temperature can make the difference between a good and great espresso.

The Pump

Unlike manual piston machines, which rely on a lever that pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure necessary to extract espresso. The pressure is created by removing tap water from a reservoir and pumping it through a heat exchanger before being shot through the ground coffee in the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both types of machines may degrade due to overuse and inadequate cleaning. Pumps are also more complicated mechanically, and can add to prices of even simple models.

Some espresso machines do away with the pump entirely and use steam pressure to brew espresso. This could lead to over-extraction since the boiler that produces steam also warms the water to boil. They also have to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize the rotary or vibration pump, with a vibrating model that uses a vibrating disc to create pressure and the rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, however rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler is what is used to heat the water to a temperature that is ideal to extract. The steam that is produced is then directed to the portafilter, which holds the espresso grounds. The steam is then channeled into the cup. In this process, the steam creates pressure that pushes through the coffee grounds. This produces a layer of crema that is then poured over. This is the hallmark of a good espresso.

There are three distinct types of espresso machines, each having distinct pumps and the temperature of the brew. There are various ways that the brew can be controlled and the size of the cup that the machine can produce.

The earliest espresso machines were steam-based. The first espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common top espresso machines machine is a semiautomatic with an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic espresso machine, you grind the beans and then tamp them yourself but the pump regulates the flow of water and pressure. This is a perfect compromise between human control and mechanised consistency.

The Filter

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

A filter also helps with flavor since it allows for a longer flowering phase. This allows the beans to let their nuances out, and allows for espresso machines a 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 and the extraction process, are still crucial.

This is where the magic happens, it's what makes espresso taste good. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy that you put the coffee grounds into, while making best cheap espresso machine.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to produce steam. The steam then pushes hot water into the grounds of coffee at high pressure. These machines are cheaper and easier to maintain than pumps-driven models. However, they are not as efficient in their capacity to create the perfect brewing conditions since they are only operating at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

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 much more mobile than electric steam-driven espresso machines.