How To Explain Machine Espresso To A 5-Year-Old

How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to make the coffee we love. What exactly does it work?

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

The Head of the Group

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter and then controlling the pressure of the extraction. There are a variety of group heads each with their own advantages and disadvantages. Some are designed for the stability of temperature while some are designed to handle pre-infusion. Others are built to control the lever. Some have a combination of features, like the E61, which is considered the most popular choice among baristas due to its capacity to offer multiple perks in a single package.

As you can see in the image above the group head is made up of many notches in which you can put your portafilter, then twist it manually to lock it in. A gasket made of rubber is positioned within the notches to make a seal when you insert your portafilter. The notches allow for precise placement of the portafilter. This is essential for an accurate extraction.

Apart from allowing you easily insert your portafilter, the group head is responsible to ensure that the temperature remains even. It does this by cycling hot water through the brew pan and around the portafilter, making sure that it is always at the correct temperature for extraction. It is crucial to keep in mind that even a small difference can make the difference between a good and a great espresso.

The Pump

In contrast to manual piston machines that use a lever to pressurize water, Rotary espresso machines rely on motorized pumps to deliver the nine atmospheric bars of pressure that are required to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are generally less expensive than piston-driven machines, and tend to last longer. However, both types of machines may degrade with overuse and insufficient cleaning. They also add mechanical complexity which can result in a high price tag on even the simplest models.

Some espresso machines do away with the pump completely and make use of steam pressure to make espresso. The drawback is that the boiler that produces steam also increases the temperature of the water to boiling, which can lead to over-extraction. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines make use of an rotary or vibrating pump, which is a vibration model that uses a vibrating disc that generates the pressure and the rotary model pushing hot water through the grounds under high speed. Both models can make excellent espresso, but rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element which heats the water to the optimal temperature to extract. The resulting steam is then transferred to the portafilter that contains the ground espresso coffee and is then funneled down into the cup. During this process, steam creates pressure that pushes through the coffee grounds. This creates a foam on top of the espresso. This is the hallmark of a good espresso.

There are three different types of espresso machines, each with distinct pumps and the temperature of the brew. There are a variety of ways to control the brew as well as the size of cup that can be produced by the machine.

The earliest espresso machines were steam types. They had one boiler to make both brew and steam, but the pressure they could produce was not very high - two bars coffeee.uk of atmospheric pressure at most. This led to the coffee tasting burnt and bitter. The modern espresso machine was invented by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso machine is a semiautomatic one with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine, you have to grind the beans and then tamp them yourself but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and mechanized quality.

The Filter

Espresso machines typically use filters that separate the grounds of the coffee from hot water. The filter is also an essential component of the machine's temp control, since it helps to prevent overheating.

A filter can also help with flavor as it allows for a longer flowering period. This allows beans to release their flavors and provides an opportunity for better extraction.

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

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

In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds with high pressure. These kinds of machines are generally less expensive and simpler to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.

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