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The No. One Question That Everyone Working In Machine Espresso Should Be Able To Answer
How Does Machine Espresso Work?

The machine espresso uses precise pressure and filtering system that is awe-inspiring to create the coffee you love. How does it work exactly?

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

The Group Head


The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the extraction. There are numerous kinds of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion features, and others are designed to control the lever. Some come with a combination of both, such as the E61. This is a popular choice among baristas as it provides a variety of advantages in a single package.

As you can see in the picture above the group head has a number of notches. You place your portafilter in these notches, then turn the head around to secure it. There is also a gasket made of rubber that is a part of the notches and helps create the seal when you insert your portafilter into the machine. The notches allow for the precise placement of the portafilter. This is essential for an efficient extraction.

Apart from allowing you easily connect your portafilter, the group head is responsible for maintaining a consistent temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is constant to extract the coffee. This is vital, because just a few degrees could be the difference between a excellent and great espresso.

The Pump

The motorized pumps used in espresso machines that rotate provide the nine atmospheric bar pressure needed to extract espresso. This is different from manually operated piston machines that employ levers. This pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.

Pumps are typically less expensive than piston-driven machines and tend to last longer, although both types of machines may be damaged by excessive use and inadequate cleaning. They also increase the complexity of mechanical systems that can lead to a high price tag on even the most basic models.

Some espresso machines use steam pressure instead of a pump to brew espresso. The drawback of this is that the boiler that produces steam also increases the temperature of the water until it reaches boiling, which can lead to excessive extraction. They also have to continuously rebuild their pressure between cups. This takes energy and time.

A large majority of espresso machines employ an rotary or a vibration pump. A vibration model utilizes an oscillating disk to create pressure, while the circular model pushes hot liquid through the ground at a fast speed. Both types of machine can make a great espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the part that heats water to an ideal temperature to extract. The steam that is created gets to the portafilter which contains the espresso coffee grounds. It is then poured into the cup. The steam creates pressure that pushes through the coffee grounds. This results in a layer of crema that is then poured over. This is one of the main characteristics of a great espresso.

There are three types of espresso makers , which differ in the type of pump they use and the degree of heat that the brew is. There are many ways to control the brew and the size of the cup that can be produced by the machine.

The earliest espresso machines were steam types. They had only one boiler to make both steam and brew, but the pressure they could generate was low - only two bars of atmospheric pressure maximum. This led to the coffee tasting burnt and bitter. This is the reason why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known espresso machine is a semiautomatic with an electric pump. These are what people imagine when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanized accuracy.

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.

It also enhances flavor, since a filter can allow for a longer bloom phase. This helps the beans to release their flavor and gives an opportunity for better extraction.

However it is crucial to remember that even a great filter could result in a bad cup of coffee, because the quality of the beans and extraction are essential.

This is where the magic happens. It's what makes espresso taste good. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy that you use to put the coffee grounds in, when making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to create steam. The steam then moves hot water through the grounds of coffee under high pressure. These machines are cheaper and easier for the user to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air pump-driven espresso machines have become more popular. They make use of an air compressor to push hot water through the ground and are much more mobile than steam-driven electric espresso machines.