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How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. What exactly is it?

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

The Head of the Group

As the name implies the group head is the place you place your portafilter while making professional espresso machine. It disperses the water into the portafilter, and then controls the pressure of the extraction. There are a variety of types of group head, each with their particular advantages and disadvantages. Some focus on temperature stability, others on pre-infusion options, and others are designed to control the lever. Some are a combination, like the E61. This is a preferred choice for baristas since it provides multiple benefits in a single package.

As you can see from the above photo the head of the group is fitted with a variety of notches. You can place your portafilter in these notches, then twist the head to lock it. There is also a rubber gasket that resides inside the notches and helps create a seal when you insert your portafilter into the machine. The notches on the head allow for a precise position of the portafilter which is necessary for a consistent extraction.

Aside from allowing you to easily insert your portafilter, the group head is responsible for maintaining an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is at the right level to extract the coffee. It is important to remember that even a small differences can make the distinction between a decent and a great espresso.

The Pump

In contrast to manual piston machines which use a lever to pressurize water, Rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure necessary for espresso extraction. This pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger prior being shot through the ground coffee inside the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which can increase the cost of even the simplest models.

Certain espresso machines eliminate the pump completely and make use of steam pressure to make espresso. This could lead to over-extraction since the boiler that produces steam also warms the water to boil. These machines also have to continuously rebuild their pressure between cups. This takes energy and time.

A large majority of espresso machines employ a rotary or vibration pump. A vibration model makes use of an oscillating disk to create pressure, while a rotating model pushes hot water through the ground at a high speed. Both types of machines are capable of producing excellent espresso, however the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to an optimal temperature to extract. The resultant steam then reaches the portafilter that contains ground espresso beans and is then pumped down into the cup. In this process, the steam causes pressure to push through the coffee grounds. This results in a whipped-up top of the espresso. This is one of the main characteristics of a good espresso.

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

The earliest espresso machines were steam types. They used a single boiler to make steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso maker is a semiautomatic machine that has an electric pump. These are the things people think of when they think of an espresso machine. With a semi-Automatic Espresso Machine - Pukkabookmarks.Com,, you must grind the beans and tamp them by hand, but the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and mechanized accuracy.

The Filter

Espresso machines typically have a filter that separates the grounds of coffee from hot water. The filter is also an essential part of the temperature control system because it stops the machine from overheating.

It also aids in flavor, as it can allow for a longer bloom time. This lets the beans let their nuances out, and allows for better extraction.

It is important to keep in mind that even the best espresso machine under 500 filter can result in a bad cup of coffee. The quality of the beans and the extraction process, remain crucial.

It's here that the magic happens. This is the reason why espresso tastes so delicious. The grouphead, sometimes referred to as the brewhead, is where the portafilter (the thing you put the coffee ground into) is located when you're 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 into the grounds of the coffee under pressure. These types of machines are usually less expensive and simpler to maintain than pump-driven models. They are however limited to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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