How Does Machine Espresso Work?

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

To make an retro espresso maker hot water is forced under high pressure through finely ground coffee. 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 you put in when making espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure of the extraction. There are numerous kinds of group heads each with its own advantages and drawbacks. Some are specifically designed for the stability of temperature while some are specifically designed to handle pre-infusion. Others are built to control the lever. Some come with a combination of both, like the E61. This is a popular choice among baristas because it offers multiple benefits in a single package.

As you can see in the image above the group head comes with numerous notches that you can place your portafilter before twisting it manually to lock it in. There is also a gasket of rubber which is located inside the notches to help create an airtight seal after inserting your portafilter into the machine. The notches allow for the precise placement of the portafilter. This is crucial for an accurate extraction.

The group head is not just able to allow you to place your portafilter easily, but it also maintains the temperature at a constant level. This is achieved by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is always at the right level for extraction. It is important to remember that even a slight difference can make the difference between a great and a excellent espresso.

The Pump

The motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure required for espresso extraction. This differs from manual piston machines which use a lever. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be cheaper and last longer than piston-driven machines. However, both kinds of machines can deteriorate because of frequent use and insufficient cleaning. Pumps are also more complex mechanically, and Machine espresso can add to the cost of even the simpler models.

Certain decent espresso machine machines can eliminate the pump entirely and utilize steam pressure to make espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of the water to the point of boiling which can cause over-extraction. These machines also have to constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines utilize an rotary or vibrating pump, which has a vibration model using a vibrating disc that generates the pressure, and a rotary model pushing hot water through the grounds under high speed. Both models are capable of producing excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the component which heats the water to the ideal temperature for extraction. The resulting steam is then transferred to the portafilter that contains the ground barista espresso machine coffee and is then funneled down into the cup. The steam generates enough pressure to push the grounds of the coffee through. This results in a whipped-up the top of the espresso. This is one of the hallmarks of a good espresso.

There are three different types of espresso machines, each having different pumps and the temperature of the brew. There are various ways that the brew can be controlled and the size of the cup the machine is capable of making.

The earliest espresso machines were steam type. The first espresso machines were steam types. This led to the coffee tasting bitter and burnt. The modern espresso machine was invented by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine, you grind the beans and then tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a fantastic solution that combines human control with mechanised consistency.

The Filter

espresso maker for home machines usually use a filter that separates the grounds of the coffee from hot water. The filter is also an essential element of the temperature control system since it helps prevent the machine from overheating.

Filters also aid in flavor because it allows for an extended flowering time. This helps the beans let their nuances out and provides an opportunity to improve extraction.

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

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

In a steam-driven espresso machine hot water is heated in an airtight container to create steam, which is then pushed through the grounds at 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 perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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