How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to create 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 major difference is in the pressure.

The Group Head

As 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 numerous kinds of group heads each with their own advantages and disadvantages. Some are designed to provide stability in temperature, while others are built to handle pre-infusion. Others are made to control the lever. Some are a combination, like the E61. This is a very popular choice for baristas since it provides multiple benefits in one package.

As you can see in the image above The group head features several notches where you place your portafilter before twisting it manually to secure it. A gasket made of rubber is placed inside the notches, which helps create a seal as you insert your portafilter. The notches permit precise placement of the portafilter. This is essential for an accurate extraction.

In addition to allowing you to easily place your portafilter in, the group head is also responsible to maintain an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is constant for extraction. This is important, as even a few degrees can mean the difference between good and great travel espresso maker.

The Pump

Motorized pumps in rotary espresso machines supply the nine atmospheric bars of pressure required for espresso extraction. This differs from manual piston machines that rely on levers. The pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior being shot through the ground coffee in the group head.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer, however both types of machines may become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase prices of even simple models.

Certain espresso machines do away with the pump completely and instead use steam pressure to brew espresso. The drawback of this is that the same boiler that produces steam also raises the temperature of water until it reaches boiling and can result in excessive extraction. Additionally the machines often have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines utilize the rotary or vibration pump, with a vibration model using a vibrating disc that generates the pressure and the rotary model pushing hot water through the grounds at high speed. Both machines can produce excellent espresso, but rotary machines are more quiet, durable and less likely to break.

The Boiler

The boiler is the part that heats water to the ideal temperature for extraction. The steam that is created is then directed to the portafilter, which contains the espresso coffee grounds. It is then poured into the cup. In this process, the steam creates pressure to push through the coffee grounds. This results in a whipped-up the top of the espresso. This is a sign of a good espresso.

There are three kinds of espresso makers, and they differ in the type of pump they employ and how hot the espresso is. There are a variety of ways to control the brew and the size of the cup that can be made by the machine.

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

The most popular espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine, you have to grind the beans and tamp them by hand. The pump controls the flow of water and pressure. This is an excellent compromise between human touch and mechanized quality.

The Filter

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

A filter can also help with flavor since it allows for an extended flowering time. This allows the beans to release their flavor and allows for a better extraction.

However, it is important to keep in mind that even a high-quality filter can make a terrible cup of coffee, because the quality of the beans and extraction is still crucial.

It's here that the magic happens. This is what makes espresso taste so good. The grouphead, often called the brew head, is the place where the portafilter (the thing you put the ground coffee into) sits when you're making espresso.

Steam-driven espresso machines make use of hot water heated in an airtight container to make steam. The steam then moves hot water through the coffee grounds under high pressure. They are less expensive and easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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