This Week's Most Popular Stories About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How exactly does it work?

Espresso is created by forcing hot water 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 the place you place your portafilter while brewing espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the extraction. There are various kinds of group head, each with their own advantages and disadvantages. Some are focused on temperature stability, some on pre-infusion options, and others are designed to control the lever. Some have a combination, such as the E61. This is a very popular choice for baristas since it provides multiple benefits in a single package.

As you can see in the picture above the group head is equipped with several notches. The portafilter is placed into these notches and turn the head around to secure it. A rubber gasket is located inside the notches, which helps make a seal when you insert your portafilter. The notches permit precise placement of your portafilter. This is essential for an efficient extraction.

The group head is not just able to allow you to put in your portafilter easily however, it also keeps an even temperature. It does this by cycling hot water through the brew pan and around the portafilter to ensure that it is always at the right temperature to extract. It is crucial to keep in mind that even a tiny variation can mean the difference between a decent and a excellent espresso.

The Pump

Unlike manual piston machines, which rely on a lever to pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure required for espresso extraction. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are generally less expensive than piston-driven machines, and tend to last longer, but both types of machines can get damaged through overuse and lack of cleaning. They also make mechanically complex that can lead to costly prices for even the most basic models.

Certain espresso machines utilize steam pressure instead of a pump for brewing espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of the water to boiling and can result in excessive extraction. In addition, these machines frequently have to restore their pressure between cups, which requires time and energy.

Many espresso machines utilize a vibration or rotary pump, which is a vibration model that uses a vibrating disc to create pressure, and an rotary model that pushes hot water through the grounds at high speed. Both types of machines can produce an excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the one that makes the water warm to the right temperature for extraction. The resulting steam reaches the portafilter that contains the ground espresso and is then pumped down into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This creates a foam on the top of the espresso. This is a hallmark of a good espresso.

There read more are three kinds of espresso machines, each having a different type of pump and the temperature of the brew. There are various ways in which the brew can be controlled, as well as the size of the cup the maker can create.

The first espresso machines were steam-type. They employed one boiler to make both steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. This resulted in the coffee tasting burnt and bitter. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they think of these machines. With a semi-automatic espresso machine, you grind the beans and tamp them by hand. The pump regulates the flow of water and pressure. This is a perfect solution that combines human control with 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 part of the temperature control system as it prevents the machine from overheating.

It also helps with flavor, as it can allow for a longer bloom phase. This helps the beans to release their flavor and gives an opportunity to improve extraction.

However it is crucial to remember that even a high-quality filter could result in a bad cup of coffee, since the quality of the beans and extraction is still vital.

This is where the magic happens, it's the thing that makes an espresso really taste good. The grouphead, also referred to as the brew head, is where the portafilter (the container you place the coffee grounds into) sits when you're making espresso.

In the steam-driven espresso machine hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at a high pressure. These machines are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited 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, espresso machines driven by a compressed air pump have become increasingly popular. They use an air compressor to push hot water through the ground. They are also more mobile than electric steam-driven espresso machines.