9 Things Your Parents Taught You About Machine Espresso

How Does Machine Espresso (125.141.133.9) Work?

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

Espresso is produced by pushing hot water under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the main difference.

The Group Head

The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure of the resulting extraction. There are many different kinds of group heads, each with their own advantages and drawbacks. Some are designed to provide stability in temperature, while others are designed to handle pre-infusion. Others are made to control the lever. Some are 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 photo the group head comes with numerous notches that you can put your portafilter, then twist it manually to secure it. A rubber gasket is located in the notches to create a seal while you insert your portafilter. The notches allow for an exact placement of the portafilter. This is crucial to ensure a consistent 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, ensuring that it's always at the right temperature to extract. It is crucial to keep in mind that even a slight deviation can make the difference between a good and a great espresso.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever that pressurize water, rotating espresso machines rely upon motorized pumps to deliver the nine atmospheric bars of pressure necessary for espresso extraction. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be more affordable and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading because of excessive use and inadequate cleaning. Pumps are also more complicated mechanically, which can increase the cost of even most basic models.

Some espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. The drawback is that the same boiler that produces steam also increases the temperature of the water to boiling which can cause excessive extraction. These machines also have to continually rebuild their pressure between cups. This takes energy and time.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model uses a rotating disk to generate pressure, while a rotating model pushes hot water through the ground at a high speed. Both machines produce great espresso, but rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler is the element which heats the water to the ideal temperature for extraction. The steam produced reaches the portafilter, which is a container for espresso grounds. It is then pumped into the cup. The steam creates pressure and pushes through the grounds of the coffee. This results in a crema on top of the espresso. This is a sign of a good espresso.

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

The first espresso machines were steam-types. They used only one boiler to make steam and brew, but the pressure they could create was minimal - two bars of atmospheric pressure at the most. This resulted in the coffee for espresso machine tasting bitter and burnt. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most common espresso maker is a semi-automatic one with an electric pump. These are the things people think of when they imagine an espresso machine. With a semi-automatic espresso machine, you must grind the beans and then tamp them by hand. However, the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised accuracy.

The Filter

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

A filter can also help with flavor because it allows for an extended flowering time. This allows the beans to release their flavor and gives an opportunity for better extraction.

However, it is important to keep in mind that even a good filter could result in a bad cup of coffee, as the quality of the beans and extraction is still important.

It's in this area that the magic takes place. This is the reason why espresso tastes so good. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy used to place the coffee grounds into, when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight tank to create steam, which then pushes the hot water through the grounds under high pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. However, they are limited in their ability to produce the perfect brewing conditions since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.

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