10 Facts About Machine Espresso That Insists On Putting You In An Optimistic Mood

How Does Machine Espresso Work?

The machine espresso uses precision pressure, and filtering technology that is amazing to make the coffee you enjoy. How does it work exactly?

To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to that of making drip coffee. However, the pressure is the major difference.

The Group Head

As the name implies, the group head is where you insert your portafilter when brewing espresso. It distributes water into the portafilter and regulates the pressure during the extraction. There are many different types of group heads each with distinct advantages and disadvantages. Some are designed for stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. There are some that have a combination of features, like the E61, which is to be the most popular among baristas because of its ability to offer multiple perks in a single package.

As you can see in the image above the group head is made up of several notches where you place your portafilter before twisting it manually to secure it. There is also a gasket made of rubber that is a part of the notches and helps create the seal when you insert your portafilter into the machine. The notches permit an exact placement of the portafilter. This is crucial to ensure an efficient extraction.

In addition to allowing you easily connect your portafilter, the group head is also responsible for maintaining a consistent temperature. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it's always at the correct temperature to extract. This is important, as just a few degrees could make the difference between a good and 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 that are required for espresso extraction. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both types of machines are susceptible to degrading due to overuse and inadequate cleaning. Pumps are also more complicated mechanically, which can raise prices of even simple models.

Some espresso machines use steam pressure instead of a pump for brewing espresso. The drawback is that the boiler that produces steam also increases the temperature of water to the point of boiling, which can lead to over-extraction. Additionally these machines are often required to restore their pressure between cups, which takes time and energy.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model employs an oscillating disk to create pressure, whereas the circular model pushes hot liquid through the ground at a fast speed. Both machines can make excellent espresso however rotary machines tend to be quieter, more durable and less likely to break.

The Boiler

The boiler heats the water to the right temperature for extraction. The resultant steam then reaches the portafilter that contains ground espresso beans and is then funneled down into the cup. The steam creates enough pressure to push the coffee grounds through. This creates a foam on top of the espresso. This is a sign of a great espresso.

There are three different types of espresso machines, each having different pumps and brew temperature. There are many ways to control the brew and the size of cup that can be made by the machine.

The first espresso machines were steam-types. They had one boiler to create both steam and brew, however, the pressure they could create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known espresso machines home maker is a semi-automatic device that has an electric pump. These are the images people have when they imagine an espresso machine. With a semi-automatic espresso machine, you need to grind the beans and tamp them by hand, but the pump provides regulated water flow and pressure. This is an excellent compromise between human touch and the mechanized quality espresso machine.

The Filter

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

Filters also aid in flavor, as it permits a longer flowering period. This allows the beans to release their flavors, and improves extraction.

It is important to remember that even the best filter can result in a bad cup of coffee. The quality of the beans and the extraction, remain vital.

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

In a steam-driven espresso Machine with grinder machine, hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds under high pressure. These kinds of machines tend to be cheaper and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to create the ideal brewing conditions, as they only operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.

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