How Does Machine Espresso Work?

Machine best espresso machine utilizes precise pressure and mind-blowing filter technology to create the perfect cup of coffee. How exactly does it work?

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

The Group Head

As the name suggests the group head is where you insert your portafilter when making espresso. It disperses the water into the portafilter, and controls the pressure of the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, whereas others on pre-infusion options, and others are designed to control the lever. Some have a combination of features, like the E61, which is to be the most popular among baristas due to its ability to offer multiple benefits in one package.

As you can see from the photo above, the group head has a number of notches. The portafilter is placed inside these notches, and then turn the head around to secure it. A gasket made of rubber is placed within the notches to create a seal while you insert your portafilter. The notches allow for an exact placement of the portafilter. This is vital for an even extraction.

The group head not only allows you to place your portafilter easily however it also keeps the temperature at a constant level. This is accomplished by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is at the right level 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 machine black friday.

The Pump

In contrast to manual piston machines which rely on a lever that pressurize water, rotating espresso machines rely upon motorized pumps to deliver 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 to being pushed through the ground coffee in the group head.

Pumps are generally less expensive and last longer than piston-driven machines. However, both types of machines can deteriorate because of excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which can raise the cost of even simpler models.

Some espresso machines employ steam pressure instead of a pump to make espresso. This can cause over-extraction because the boiler that makes steam also warms the water to boil. In addition, these machines frequently have to restore their pressure between cups, which requires time and energy.

Many espresso machines make use of either a vibration or rotary pump. A vibration model uses the vibrating disk to create pressure, whereas the rotating model pushes hot water through the ground at a fast speed. Both machines espresso machines can produce excellent espresso but rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is the part that heats the water to the ideal temperature for extraction. The resulting steam reaches the portafilter, which contains the ground espresso coffee and is then pumped down into the cup. The steam generates enough pressure to push the grounds of coffee through. This results in a layer crema on top. This is the hallmark of a good espresso.

There are three kinds of espresso makers. They differ in the type of pump they employ and the degree of heat that the coffee is. There are different ways in which the brew could be controlled and the size of the cup that the machine is capable of making.

The first espresso machines were steam-type. They had a single boiler to make both brew and steam, but the pressure they could produce was not very high - two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most popular espresso machine is a semiautomatic that has an electric pump. These are the things people think of when they think of an espresso coffee machine home (killer deal) machine. Semi-automatic machines require you to grind and tamp the beans yourself however the pump controls the water flow and pressure. This is a fantastic compromise between human control and mechanised accuracy.

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from hot water. The filter is also a vital component of the machine's temperature control, as it prevents overheating.

It also improves flavor as a filter allows for a more prolonged bloom time. This lets the beans release their nuances, and also allows for better extraction.

However, it is important to remember that even a great filter could result in a bad cup of coffee, as the quality of the beans and extraction is vital.

It's here that the magic takes place. This is the reason why espresso tastes so good. The grouphead, often referred to as the brew head, is the place where the portafilter (the thingy you put the ground coffee in) is located when you're making espresso.

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

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