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How Does Machine Espresso Work?

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

espresso coffee machines is made by forcing hot water at high pressure through finely ground coffee. The process is similar to that of making drip coffee. However it is the pressure that makes the main difference.

The Head of the Group

The name implies, the group head is where you place your portafilter while making espresso. It distributes water into the portafilter, and regulates the pressure of the extraction. There are a variety of group heads each with their own advantages and drawbacks. Some focus on temperature stability, some on pre-infusion options, and others are designed to control the lever. There are even some that have a combination of features, like the E61 that is the classic choice among many baristas due to its capacity to offer multiple benefits in a single package.

As you can see in the photo above the group head comes with many notches in which you can place your portafilter and then twist it manually to lock it in. A gasket made of rubber is positioned inside the notches to help create a seal while you insert your portafilter. The notches on the head allow for an exact position of the portafilter which is necessary to ensure an efficient extraction.

The group head not only allows you to put in your portafilter easily however, it also keeps a constant temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant to extract the coffee. This is vital, because just a few degrees could make the difference between a good and excellent espresso.

The Pump

Motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure that is required to extract espresso. This differs from manually operated piston machines that employ levers. The pressure is built by pumping water through a heat exchanger and then through the ground coffee machines espresso.

Pumps tend to be cheaper and last longer than piston-driven machines. However, both types of machines can deteriorate due to overuse and poor cleaning. They also create mechanical complexity and can lead to an expensive price for even the simplest models.

Certain espresso machines utilize steam pressure instead of a pump to brew espresso. This can result in over-extraction because the boiler that produces steam also warms the water to boil. They also have to continuously rebuild their pressure between cups. This takes energy and time.

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

The Boiler

The boiler is what will heat the water to the right temperature for extraction. The steam created reaches the portafilter, which holds the espresso grounds. It is then funneled into the cup. During this process, steam creates pressure and pushes through the coffee and espresso maker grounds. This creates a layer crema on top. This is one of the hallmarks of a great espresso.

There are three kinds of espresso machines, each having different types of pumps and the temperature of the brew. There are different ways to control the strength of the brew and the size of the cup that can be made by the machine.

The earliest espresso machines were steam-based. The earliest espresso machines were steam types. This led to the coffee tasting bitter and burnt. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso maker is a semiautomatic machine with an electric pump. When people think of espresso machines, they think of these machines. With a semi-automatic espresso coffee machine machine (enquiry), you need to grind the beans and then tamp them by hand, but the pump provides regulated water flow and pressure. This is a great compromise between the human touch and the mechanized consistency.

The Filter

Typically, espresso machines use filters that separate the grounds of coffee as they move through the hot water. The filter is also a vital part of the temperature control system as it prevents the machine from overheating.

A filter can also help with flavor since it allows for the beans to flower for a longer period of time. This allows the beans to let their nuances out, and allows for better extraction.

It is important to remember that even the finest filter can produce a bad cup of coffee. The quality of the beans and the extraction process are still very important.

This is where the magic happens, it's what makes espresso taste great. The grouphead (also called the brewhead) is where you place the portafilter - the thingy that you put the grounds of your coffee into when making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at high pressure. These types of machines are typically less expensive and easier to maintain than pump-driven models. However, they are not as efficient 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, espresso machines powered by compressed air-pump are becoming increasingly popular. They utilize an air compressor to push hot water through grounds and are more portable than electric steam-driven machines.