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How Does Machine Espresso Work?

Machine retro espresso maker uses precision pressure and mind-blowing filter technology to create the perfect cup of coffee. What exactly is it?

In order to make espresso hot water is forced under high 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 that you put in when making barista espresso machine. It disperses the water into the portafilter, and controls the pressure of the extraction. There are a variety of group heads each with their own advantages and drawbacks. Some are designed for temperature stability while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some have a combination of features, such as the E61, which is to be the most popular among baristas because of its ability to offer multiple benefits in a single package.

As you can see from the image above the group head is equipped with several notches. You can place your portafilter in these notches and then turn the head around to secure it. There is also a gasket of rubber which is located inside the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head allow for an exact placement of the portafilter, which is essential for an efficient extraction.

The group head is not just able to allow you to put in your portafilter easily however, it also keeps an even temperature. It does this by circulating hot water through the brew pan and around the portafilter, ensuring that it is always at the correct temperature to extract. It is important to remember that even a tiny difference can make the difference between a good and a great espresso.

The Pump

Contrary to manual piston machines that use a lever to pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure necessary for espresso extraction. The pressure is created by drawing tap water from a reservoir, and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.

Pumps are generally more affordable and last longer than piston-driven machines. However, both kinds of machines may degrade due to excessive use and insufficient cleaning. They also make mechanically complex and can lead to the cost of even the most basic models.

Some espresso machines make use of steam pressure instead of a pump to brew espresso. The drawback is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling which could lead to over-extraction. These machines also have to continually rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines use the rotary or vibration pump, which has a vibration model using a vibrating disc to create pressure and an rotary model that pushes hot water through the grounds at high speed. Both machines can make great espresso, but rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is the one that makes the water warm to the right temperature for extraction. The steam created will eventually reach the portafilter, which is the container that holds the espresso coffee grounds. It is then poured into the cup. The steam creates enough pressure to push the grounds of the coffee through. This produces a layer of crema that is then poured over. This is one of the main characteristics of a good espresso.

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

The first espresso machines were steam type. They had a single boiler to make both steam and brew, however, the pressure they could generate was low - only two bars of atmospheric pressure at most. This led to the coffee tasting bitter and burnt. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic one with an electric pump. These are the images people have when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans by yourself however the pump controls the water flow and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

Espresso machines typically use a filter that separates the grounds of the coffee from hot water. The filter is also an essential part of the machine's temperature control, as it prevents overheating.

A filter can also help with flavor, as it permits a longer flowering period. This allows the beans to let their nuances out, and improves extraction.

However, it is important to remember that even a high-quality filter could result in a bad cup of coffee, since the quality espresso machine of the beans and extraction are vital.

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

In a steam-driven espresso machine hot water is heated in an airtight tank to create steam. This is then pushed through the grounds at high pressure. These machines are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machines powered by compressed air-pump have become increasingly popular. They utilize an air compressor to force the hot water through the grounds and are significantly more portable than electric steam-driven machines.