How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to make the delicious coffee espresso machines we enjoy. But how exactly does it work?

To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to that of making drip coffee. However it is the pressure that makes the main difference.

The Group Head

The name implies the group head is where you put your portafilter in when making espresso. It disperses water into the portafilter and regulates the pressure of extraction. There are many different kinds of group head, each with their own advantages and drawbacks. Some are designed to provide stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some have a combination, such as the E61. This is a popular choice among baristas because it offers multiple advantages in a single package.

As you can see from the picture above the head of the group is fitted with a variety of notches. It is possible to place your portafilter in these notches and then twist the head to lock it. A gasket made of rubber is placed within the notches to make a seal when you insert your portafilter. The notches on the head permit an exact location of the portafilter which is essential for an efficient extraction.

The group head is not just able to allow the portafilter to be inserted easily, but it also maintains an even temperature. It does this by circulating hot water through the brew pan and around the portafilter, ensuring that it is always at the right temperature for extraction. This is important, as even a few degrees can be the difference between a good and excellent espresso.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever that pressurize water, Rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure required for espresso extraction. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to overuse and poor cleaning. They also add mechanical complexity which can result in a high price tag on even the simplest models.

Some espresso machines for home machines employ steam pressure instead of a pump to brew espresso. The disadvantage of this is that the same boiler that produces steam also raises the temperature of water to boiling which can cause excessive extraction. In addition, these machines frequently have to rebuild their pressure between cups, which requires time and energy.

Many espresso machines make use of a rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, while the rotary model pushes hot water through the ground at high speed. Both machines can make excellent espresso but rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler is the component which heats the water to the optimal temperature for extraction. The steam that is created reaches the portafilter, which is a container for espresso grounds. It is then poured into the cup. During this process, steam creates pressure to push through the grounds of the coffee. This creates a foam on top of the espresso. This is a sign of a great espresso.

There are three kinds of espresso makers, and they differ in the kind of pump they use and how hot the mini espresso machine is. There are also different ways in which the brew can be controlled as well as the size of the cup the machine can make.

The first espresso machines were steam type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most common espresso machine is a semiautomatic model with an electric pump. These are the things people think of when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself, but the pump regulates the water flow and pressure. This is an excellent compromise between human touch and the mechanized accuracy.

The Filter

Typically, espresso machines utilize a filter to separate out the grounds of coffee as they move through the hot water. The filter is also a crucial element of the temperature control system, because it stops the machine from overheating.

A filter also helps with flavor, as it permits the beans to flower for a longer period of time. This allows beans to release their nuances and gives an opportunity to improve extraction.

It is important to remember that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction process, are still crucial.

It's in this area that the magic happens. This is what makes espresso taste so delicious. The grouphead (also known as the brewhead) is where you put the portafilter, the device that you put the coffee grounds in, while making espresso.

Steam-driven espresso machines Espresso Machines make use of hot water that is heated inside an airtight container to create steam. The steam then pushes hot water through the coffee grounds under high pressure. These types of machines tend to be less expensive and easier to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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