The 9 Things Your Parents Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and amazing filter technology to make the perfect cup of coffee. How exactly does it work?

In order to make espresso hot water is forced under 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 name implies, the group head is where you place your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter and then controlling the pressure that results from the extraction. There are various kinds of group heads each with its own advantages and drawbacks. Some are focused on temperature stability, some on pre-infusion capabilities, while others are designed to control the lever. Some have a combination, like the E61. This is a popular choice among baristas since it provides multiple benefits in one package.

As you can see in the picture above the group head is equipped with several notches. You can place your portafilter inside these notches, and then twist the head to secure it. There is also a rubber gasket that is a part of the notches, which helps create an airtight seal after inserting your portafilter into the machine. The notches permit precise placement of the portafilter. This is crucial for a consistent extraction.

The group head is not just able to allow you to insert your portafilter easily but also maintains a constant temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is at the right level for extraction. This is vital, because even a few degrees can be the difference between a good and excellent buy espresso machine.

The Pump

The motorized pumps used in rotary espresso machines supply the nine atmospheric bars of pressure required for espresso extraction. This differs from manual piston machines that rely on a lever. This pressure is generated 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 kinds of machines may degrade because of frequent use and poor cleaning. They also create mechanical complexity and can lead to the cost of even the simplest models.

Certain espresso machines do away with the pump completely and instead utilize steam pressure to make espresso. This can cause over-extraction because the boiler that produces steam also warms the water to boil. Additionally, these machines frequently have to restore their pressure between cups, which requires time and energy.

Many commercial espresso machine machines make use of either a rotary or vibration pump, which is a vibration model using a vibrating disc that generates the pressure, and a rotary model pushing hot water through the grounds at high speed. Both machines produce great espresso, but rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler is used to heat the water to the right temperature for extraction. The steam created will eventually reach the portafilter, which holds the espresso grounds. It is then poured into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This creates a crema on top of the espresso. This is a hallmark of a great espresso.

There are three types of espresso makers, and they differ in the type of pump they use and how hot the coffee is. There are a variety of ways to control the brew as well as the size of cup that can be produced by the machine.

The first espresso machines were steam type. They had one boiler to make both brew and steam, however the pressure they were able to produce was very low - just two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most well-known espresso maker is a semi-automatic machine with an electric pump. These are the images people have when they imagine an espresso machine. If you have a semi-automatic machine you have to grind the beans and tamp them yourself but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and mechanized accuracy.

The Filter

Espresso machines typically use filters that separate the grounds of coffee from hot water. The filter is also a vital element of the machine's temperature control, since it stops overheating.

It also improves flavor, as a filter allows for a more prolonged bloom phase. This allows beans to release their flavor and gives the chance for better extraction.

However, it is important to remember that even a good filter can produce a bad cup of coffee as the quality of the beans and extraction are vital.

It's in this area that the magic takes place. This is what makes espresso taste so delicious. The grouphead, also referred to as the brew head, is where the portafilter (the device you put the coffee ground into) is placed when you're making buy espresso machines.

Steam-driven espresso machines make use of hot water that is heated in an airtight vessel to create steam. The steam then pushes hot water through grounds of coffee at high pressure. These kinds of machines are generally less expensive and easier to maintain than pumps-driven models. However, they are limited in their ability to produce the ideal brewing conditions, because they 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 become more popular. They use an air-compressor to force hot water into the ground, and are more mobile than steam-driven electric barista espresso coffee machine machines.