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How Does Machine Espresso Work?

The machine espresso makes use of precision pressure, and a filtering technology that is amazing to create the coffee you love. How does it work exactly?

Espresso is made by pushing hot water at high pressure through finely-ground coffee. The process is similar to making drip coffee. However, the pressure is the main difference.

The Group Head

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter and controlling the pressure of the resulting extraction. There are many different types of group heads, each with its own advantages and disadvantages. Some are designed for stability of temperature while others are designed to handle pre-infusion. Some are designed to control the lever. Some have a combination of features, like the E61 one, which is to be the most popular among baristas because of its ability to offer multiple perks in one package.

As you can see in the image above the group head comes with several notches where you place your portafilter before twisting it manually to secure it. There is also a gasket of rubber which is located inside 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 vital 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 basin, ensuring that the temperature is at the right level to extract the coffee. It is important to note that even a slight variation can mean the difference between a decent and a excellent espresso.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bars of pressure required for espresso extraction. This differs from manually operated piston machines that employ a lever. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee and espresso maker.

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

Some espresso machines employ steam pressure instead of a pump in order to brew espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of the water to boiling, which can lead to excessive extraction. Additionally the machines often have to restore their pressure between cups, which takes time and energy.

A majority of espresso machines use the rotary or vibration pump, with a vibration model that uses a vibrating disc that generates the pressure, and rotating models that push hot water through the grounds at high speed. Both models can make excellent best espresso machine under 200, but rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the component that heats water to an ideal temperature for extraction. The resulting steam reaches the portafilter that contains the ground espresso machine black friday and is then pumped into the cup. During this process the steam causes enough pressure to push the coffee grounds through. This results in a layer crema that is then poured over. This is one of the hallmarks of a great espresso.

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

The earliest espresso machines were steam type. They had only one boiler to make both brew and steam, however the pressure they were able to produce was not very high - two bars of atmospheric pressure, at most. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso maker is a semi-automatic espresso machine machine with an electric pump. These are what people imagine when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans by yourself The pump, however, regulates the flow of water 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 the coffee as they go through the hot water. The filter is also a vital part of the temperature control system because it stops the machine from overheating.

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

However, it is important to remember that even a high-quality filter can make a terrible cup of coffee, since the quality of the beans and extraction are crucial.

It's here that the magic happens. This is the reason why espresso tastes so good. The grouphead (also known as the brewhead) is where you place the portafilter, which is the thingy that you use to put the coffee grounds in, when making espresso.

Steam-driven espresso machines use hot water heated in an airtight container to make steam. The steam then pushes hot water into the grounds of coffee under high pressure. These machines are less expensive and easier for the owner to maintain than pumps-driven models. However, they are not as efficient in their ability to provide the perfect brewing conditions since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.

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