How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it?

To make an compact espresso machine hot water is pushed under pressure through finely ground coffee espresso machine. The process is similar to making drip coffee however the main difference lies in the pressure.

The Group Head

The group head is the portafilter that you insert when brewing espresso. It is responsible for dispersing water into the portafilter and controlling the pressure that results from the extraction. There are several different types of group head each with its unique advantages and drawbacks. Some are designed to provide temperature stability while others are designed to handle pre-infusion. Others are made to control the lever. Some have a combination, such as the E61. This is a popular choice among baristas as it provides a variety of benefits in a single package.

As you can see in the above image The group head features several notches to place your portafilter and then twist it manually to lock it in. There is also a gasket made from rubber which is located inside the notches and helps to create a seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is vital for an efficient extraction.

Aside from allowing you to easily connect your portafilter, the group head is responsible to ensure that the temperature remains even. It does this by cycling hot water through the brew pan and around the portafilter, ensuring that it is always at the right temperature to extract. It is important to note that even a few degree deviation can make the difference between a decent and a great espresso.

The Pump

Contrary to manual piston machines which rely on a lever that pressurize water, Rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure required to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive than piston-driven models, and they tend to last longer, but both types of machines could become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase the price of even the most basic models.

Some espresso machines employ steam pressure instead of a pump to brew espresso. This could lead to over-extraction since the boiler that makes steam also heats the water until it comes to a boil. These machines also have to constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines utilize the rotary or vibration pump, with a vibration model that uses a vibrating disc to create pressure, and a rotary model pushing hot water through the grounds under high speed. Both machines produce great small espresso machine but rotary machines are more quiet, durable and less likely to break.

The Boiler

The boiler will heat the water to the ideal temperature for extraction. The steam created is then directed to the portafilter, which is the container that holds the espresso coffee grounds. The steam is then channeled into the cup. During this process, the steam creates pressure that pushes through the coffee grounds. This results in a whipped-up top of the espresso. This is a sign of a good espresso.

There are three kinds of espresso makers. They differ in the kind of pump they use and how hot the espresso is. There are different ways that the brew may be controlled, as well as the dimensions of the cup the machine is capable of making.

The earliest espresso machines were steam type. They had 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 burnt. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern professional espresso machine machine.

The most commonly used espresso machine is a semiautomatic one with an electric pump. This is what people envision when they think of an barista espresso machine maker. With a semi-automatic machine you grind the beans and then tamp them by hand. The pump is able to regulate the flow of water and pressure. This is an excellent compromise between human touch and the mechanized accuracy.

The Filter

Espresso machines typically have filters that separate the grounds of the coffee from hot water. The filter is also an essential component of the machine's temp control, since it helps to prevent overheating.

A filter can also help with flavor since it allows for a longer flowering period. This allows beans to let their nuances out and provides an opportunity for better extraction.

It is important to keep in mind that even the best filter could result in a poor cup of coffee. The quality of the beans, as well as the extraction, remain vital.

This is where the magic happens. It's what makes an espresso really taste good. The grouphead, sometimes called the brew head, is where the portafilter (the thing you put the coffee grounds into) is placed when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to produce steam, which is then pushed through the grounds under high pressure. These kinds of machines tend to be less expensive and simpler 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. However, the perfect shot requires 9-10 bars.

In recent years, compressed air-pump-driven espresso machines have become more popular. They utilize an air compressor to force hot water into the grounds and are much more portable than electric steam-driven machines.