9 Things Your Parents Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the coffee we love. What exactly is it that makes it work?

Espresso is made by forcing hot water at high 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 group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are various kinds of group heads, each with their distinct advantages and drawbacks. Some are designed for temperature stability while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some have a combination, like the E61. This is a favorite among baristas because it offers multiple benefits in a single package.

As you can see from the image above, the group head is fitted with several notches. You place your portafilter in these notches and then twist the head to lock it. There is also a gasket made of rubber that resides inside the notches to help create an airtight seal after inserting your portafilter into the machine. The notches on the head permit a precise location of the portafilter which is crucial to ensure an efficient extraction.

The group head does not just allow the portafilter to be inserted easily however, it also keeps an even temperature. It does this by cycling hot water through the brew pan and around the portafilter, ensuring that it's always at the right temperature to extract. This is crucial, since just a few degrees could make the difference between good and great espresso.

The Pump

The motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines that rely on levers. The pressure builds by drawing tap water from a reservoir, and pumping it through a heat exchanger before being pumped through the ground coffee in the group head.

Pumps are generally less expensive than piston-driven machines and tend to last longer, but both types of machines could degrade with overuse and insufficient cleaning. They also create mechanical complexity, which can result in costly prices for even the most basic models.

Some espresso machines do away with the pump entirely and employ steam pressure to create espresso. This could lead to over-extraction since the boiler that produces steam also heats the water to boil. The machines also need to continuously rebuild their pressure between cups. This takes energy and time.

Many espresso machines use a rotary or vibration pump. A vibration model uses the vibrating disk to create pressure, while a Rotary model pushes hot coffee through the ground at a high speed. Both machines can make excellent espresso machines for home, however rotary machines are more stable, quieter and less likely to break.

The Boiler

The boiler is the one that heats the water to the right temperature to extract. The steam produced gets to the portafilter which holds the espresso grounds. It is then funneled into the cup. During this process, steam creates pressure and pushes through the grounds of the coffee. This creates a foam on the top of the espresso. This is a sign of a great espresso.

There are three kinds of espresso makers. They differ in the type of pump they use and how hot the espresso is. There are various ways in which the brew can be controlled as well as the size of the cup that the machine is capable of making.

The earliest espresso machines were steam types. The first espresso machines were steam types. The coffee tasted bitter and burned. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso maker is a semi-automatic machine that has an electric pump. These are the images people have when they imagine an espresso machine. With a semi-automatic machine, you grind the beans and tamp them by hand, but the pump provides regulated water flow and pressure. This is a perfect compromise between human control and mechanised reliability.

The Filter

Typically, espresso machines use filters to separate the coffee grounds as they pass through the hot water. The filter is also a vital element of the machine's temperature control, as it prevents overheating.

It also improves flavor, as it allows for a longer bloom time. This allows the beans to release their flavor and also allows for better extraction.

It is important to remember that even the best small espresso machine filter can make a bad cup of coffee. The quality of the beans as well as the extraction, are still very important.

This is where the magic happens, it's the thing that makes espresso coffee makers taste great. The grouphead (also known as the brewhead) is where you put the portafilter, the device that you put the grounds of your coffee into when making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds with high pressure. They are less expensive and are easier for the user to maintain than pumps-driven models. However, they are limited in their ability to create the ideal conditions for brewing because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

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