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

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the perfect cup of coffee. How exactly does it work?

To make an espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Head of the Group

The name implies the group head is where you put your portafilter in when making espresso. It is responsible for dispersing water into the portafilter and then controlling the pressure that results from the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, some 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 favorite among baristas as it provides a variety of benefits in a single package.

As you can see in the above image the group head is made up of numerous notches that you can place your portafilter and twist it manually to secure it. There is also a gasket made of rubber which is located inside the notches to help create a seal when you insert your portafilter into the machine. The notches on the head permit a precise position of the portafilter which is vital for an even extraction.

Aside from allowing you to effortlessly insert your portafilter the group head is 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 constant to extract the coffee machine espresso. This is vital, because just a few degrees could make the difference between a good and excellent espresso.

The Pump

Contrary to manual piston machines which rely on a lever that pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure required for espresso extraction. The pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger prior to being pushed through the ground coffee inside the group head.

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

Some espresso machines use steam pressure instead of a pump in order to brew espresso coffee machines uk [official website]. This can lead to over-extraction as the boiler that makes steam also warms the water to boil. These machines also have to constantly rebuild their pressure between cups. This requires energy and time.

A majority of espresso machines utilize an rotary or a vibration pump. A vibration model makes use of a rotating disk to generate pressure, whereas the rotary model pushes hot water through the ground at a rapid speed. Both types of machines are capable of producing excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler will heat the water to the perfect temperature to extract. The resulting steam is then transferred to the portafilter which holds the ground espresso machine uk coffee, and gets funnelled down into the cup. In this process, the steam creates pressure that pushes through the coffee grounds. This results in a layer of crema on top. This is the hallmark of a great espresso.

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

The earliest espresso machines were steam types. They employed only one boiler to make steam and brew, but the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This resulted in the best coffee espresso machine tasting burnt and bitter. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used 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 grind the beans and then tamp them by hand. The pump is able to regulate the flow of water and pressure. This is an excellent compromise between human touch and 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 a vital component of the machine's temperature control, as it helps prevent overheating.

A filter also improves flavor because it allows for a longer flowering period. This allows the beans to release their flavor and gives an opportunity to improve extraction.

It is important to keep in mind that even the finest filter can result in a bad cup of coffee. The quality of the beans, and the extraction process are still very important.

It's in this area that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead, often referred to as the brewhead, is where the portafilter (the thingy you put the ground coffee in) is located when you're making espresso.

Steam-driven espresso machines use hot water heated in an airtight vessel to create steam. The steam then moves hot water through 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 ideal conditions for brewing because they operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bar.

In recent years, compressed air pump-driven espresso machines have been gaining popularity. They use an air compressor to force hot water through the ground and are much more mobile than electric espresso maker steam-driven espresso machines.