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How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and mind-blowing filter technology to make the perfect cup of coffee. What exactly is it?

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

As the name suggests, the group head is the place you place your portafilter while brewing espresso. It disperses the water into the portafilter, and then regulates the pressure during the extraction. There are numerous kinds of group heads, each with its own advantages and drawbacks. Some are designed for temperature stability 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 that is the classic choice among many baristas due to its capacity to provide multiple benefits in a single package.

As you can see in the picture above the group head is fitted with a variety of notches. You can place your portafilter inside these notches, and then turn the head around to secure it. There is also a gasket of rubber that is a part of the notches and helps to create the seal when you insert your portafilter into the machine. The notches on the head allow for an exact location of the portafilter which is necessary to ensure a consistent extraction.

The group head does not just allow you to insert your portafilter easily however it also keeps the same temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant for extraction. This is crucial, since just a few degrees could mean the difference between excellent and great espresso.

The Pump

Unlike manual piston machines, which rely on a lever to pressurize water, Rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure that are required for espresso extraction. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven machines, and tend to last longer. However, both types of machines can get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, and can add to the price of even the simple models.

Some espresso machines espresso remove the pump completely and instead use steam pressure to brew espresso. This can cause over-extraction because the boiler that makes steam also warms the water to boil. In addition these machines espresso typically have to rebuild their pressure between cups, which requires time and energy.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model uses a vibrating disk to generate pressure, whereas a rotary model pushes hot water through the ground at a fast speed. Both machines can make great barista espresso machine, but rotary machines are more stable, quieter and less likely to break.

The Boiler

The boiler is the one that makes the water warm to the right temperature for extraction. The resultant steam then reaches the portafilter containing the ground espresso coffee, and is then pumped down into the cup. During this process the steam causes enough pressure to push the coffee grounds through. This results in a whipped-up top of the espresso. This is the hallmark of a good espresso.

There are three different types of espresso machines, each with a different type of pump and brew temperature. There are many ways to control the strength of the brew and the size of cup that can be made by the machine.

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

The most commonly used espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the flow of water and pressure. This is an excellent compromise between human touch and mechanized accuracy.

The Filter

Typically, espresso maker machines employ a filter to separate out the grounds of coffee when they pass through the hot water. The filter is also a crucial component of the temperature control system since it helps prevent the machine from overheating.

A filter also helps with flavor because it allows for a longer flowering period. This lets the beans let their nuances out, and allows for a better extraction.

However it is crucial to remember that even a top filter can produce a bad cup of coffee, as the quality of the beans and extraction is still essential.

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 grounds of your coffee into while making best espresso machine under 200.

Steam-driven espresso machines use hot water that is heated inside an airtight vessel to create steam. The steam then moves hot water through the grounds of coffee at high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent times, espresso machines powered by compressed air-pump have become increasingly popular. They use an air-compressor to force hot water into the ground and are much more mobile than electric steam-driven espresso machines.