How Does Machine Espresso Work?

The machine espresso uses precise pressure, as well as a filtering system that is awe-inspiring to create the coffee you enjoy. What exactly does it work?

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

The Head of the Group

The group head is the portafilter that you place in the espresso maker when making it. It disperses the water into the portafilter and controls the pressure of the extraction. There are various kinds of group heads each with its unique advantages and disadvantages. Some are focused on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. There are also some that have a combination of features, like the E61, which is to be the most popular among baristas because of its ability to offer multiple benefits in one package.

As you can see in the image above the group head comes with several notches where you put your portafilter, then twist it by hand to secure it. A gasket of rubber is situated within the notches to create a seal as you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is essential to ensure an even extraction.

Apart from allowing you easily place your portafilter in, the group head is also responsible to maintain an even temperature. It does this by circulating hot water through the brew basket and around the portafilter to ensure that it is always at the correct temperature to extract. This is important, as even a small difference in temperature can make the difference between good and excellent espresso.

The Pump

The motorized pumps used in espresso machines that rotate provide the nine atmospheric bar pressure needed for espresso extraction. This differs from manually operated piston machines that employ a lever. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven machines, and tend to last longer, however both types of machines may get damaged through overuse and lack of cleaning. They also make mechanically complex and can lead to the cost of even the most basic models.

Some espresso machines for home machines remove the pump completely and instead make use of steam pressure to make espresso. This can lead to over-extraction as the boiler that makes steam also heats the water to boil. In addition the machines often have to rebuild their pressure between cups, which takes time and energy.

A large majority of espresso machines employ an rotary or a vibration pump. A vibration model uses an oscillating disk to create pressure, while the rotating model pushes hot water through the ground at a rapid speed. Both machines can make great espresso, but rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler is the component that heats water to an ideal temperature to extract. The resulting steam reaches the portafilter, which contains the ground espresso and is then pumped into the cup. During this process, steam creates pressure and pushes through the coffee grounds. This produces a layer of crema on top. This is the hallmark of a great espresso.

There are three kinds of espresso makers, and they differ in the type of pump they employ and how hot the coffee is. There are a variety of ways in which the brew could be controlled, as well as the size of the cup that the machine can produce.

The first espresso machines were steam-type. They employed only one boiler to make steam and brew, but the pressure they could generate was low - only two bars of atmospheric pressure at most. The coffee tasted bitter and burned. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most commonly used espresso machine is a semiautomatic model with an electric pump. These are what people imagine when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself however the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

Typically, espresso machines utilize a filter to separate out the grounds of the coffee as they go through the hot water. The filter is also an important part of the temperature control system as it prevents the machine from overheating.

It also enhances flavor, as a filter allows 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 keep in mind that even a high-quality filter could result in a bad cup of coffee, as the quality of the beans and extraction is still crucial.

This is where the magic happens, and it's what makes espresso machine black friday taste great. The grouphead, also referred to as the brew head, is the place where the portafilter (the thingy you put the coffee ground into) is placed when you're making espresso.

Steam-driven espresso coffee machine with milk frother machines make use of hot water heated in an airtight vessel to create steam. The steam then pushes hot water into the grounds of coffee under high pressure. These kinds of machines tend to be less expensive and easier to maintain than pump-driven models. They are however limited to create the perfect conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9 bar espresso machine-10 bars.

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