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How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the coffee we love. What exactly does it work?

Espresso is made by pushing hot water 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 you put in when making espresso. It distributes water into the portafilter, and then regulates the pressure during the extraction. There are several different types of group heads each with its distinct advantages and drawbacks. Some are specifically designed for stability of temperature while others are designed to handle pre-infusion. Others are made to control the lever. Some come with a combination of both, such as the E61. This is a preferred choice for baristas because it offers multiple advantages in one package.

As you can see in the image above the group head comes with several notches to place your portafilter before twisting it with your hands to lock it in. A rubber gasket is located within the notches to create a seal as you insert your portafilter. The notches on the head permit an exact position of the portafilter which is necessary for a consistent extraction.

Aside from allowing you to effortlessly insert your portafilter the group head is also responsible to ensure that the temperature remains even. This is done by cycling hot water around the portafilter and through the brew-basket, ensuring that the temperature is at the right level for extraction. It is crucial to keep in mind that even a small differences can make the distinction between a good and a great espresso.

The Pump

In contrast to manual piston machines which rely on a lever that pressurize water, Rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure necessary to extract espresso. This pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger before being pumped through the ground coffee in the group head.

Pumps are typically cheaper and last longer than piston-driven machines. However, both kinds of machines espresso are susceptible to degrading because of frequent use and insufficient cleaning. They also make mechanically complex and can lead to a high price tag on even the simplest models.

Certain espresso machines do away with the pump completely and instead make use of steam pressure to make espresso. This can lead to over-extraction as 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 Italian espresso machines time.

A majority of espresso machines use either a rotary or vibration pump, which has a vibration model that uses a vibrating disc to create the pressure, and an rotary model that pushes hot water through the grounds under high speed. Both machines produce great espresso however rotary machines tend to be more stable, quieter and less likely to break.

The Boiler

The boiler is the part that heats water to the optimal temperature to extract. The steam that is created gets to the portafilter which is a container for espresso grounds. It is then poured into the cup. During this process the steam creates enough pressure to push the grounds of the coffee through. This results in a crema on top of the espresso. This is the hallmark of a great espresso home machine.

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

The first espresso machines were steam type. They employed one boiler to create both steam and brew however the pressure they were able to create was minimal - two bars of atmospheric pressure, at most. The coffee tasted bitter and burned. The modern espresso machine was invented by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso machine with milk frother maker is a semiautomatic machine that has an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine you must grind the beans and then tamp them by hand. The pump is able to regulate the flow of water and pressure. This is a great combination of human control and mechanized reliability.

The Filter

Typically, espresso machines have filters to separate the grounds of coffee as they move through the hot water. The filter is also a vital component of the machine's temp control, since it helps to prevent overheating.

It also improves flavor, since a filter allows for a more prolonged bloom time. This helps the beans release their flavors and provides an opportunity to improve extraction.

It is important to remember that even the best filter can make a bad cup of coffee. The quality of the beans, and the extraction, remain crucial.

This is where the magic happens. It's what makes espresso taste good. The grouphead (also called the brewhead) is where you place the portafilter, the device that you put the coffee grounds into, when making espresso.

In the steam-driven espresso machine black friday [bbs.mofang.com.tw] machine hot water is heated in an airtight tank to produce steam, which is then pushed through the grounds at a high pressure. They are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited in their ability for creating the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air-pump-driven retro espresso maker machines have been gaining popularity. They utilize an air compressor to push hot water through grounds, and are far more portable than electric steam-driven machines.