Nine Things That Your Parent Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso uses precision pressure and amazing filter technology to make the coffee we love. How exactly does it work?

Espresso is made by pushing hot water under pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.

The Group Head

As the name implies the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the extraction. There are many different types 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 include a combination like the E61. This is a very popular choice for baristas as it provides a variety of advantages in one 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 by hand to lock it in. There is also a gasket of rubber that is a part of the notches and helps create the seal when you insert your portafilter into the machine. The notches on the head permit a precise location of the portafilter which is necessary for a consistent extraction.

The group head not only lets the portafilter to be inserted easily, but it also maintains a constant temperature. This is achieved by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is at the right level to extract the coffee. It is important to note that even a few degree deviation can make the difference between a good and great espresso.

The Pump

In contrast to piston machines that are manually operated, which use a lever to pressurize water, the rotary espresso machines use motorized pumps to deliver the nine atmospheric bars of pressure that are required for espresso extraction. This pressure is generated 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 may degrade because of frequent use and inadequate cleaning. They also add mechanical complexity that can lead to a high price tag on even the most basic models.

Certain espresso machines remove the pump completely and employ steam pressure to create best home espresso machine. This can result in over-extraction because the boiler that produces steam also heats the water to boil. In addition these machines typically have to restore their pressure between cups, which requires time and energy.

A large majority of espresso machines employ a rotary or vibration pump. A vibration model makes use of a vibrating disk to generate pressure, while the Rotary model pushes hot coffee through the ground at a fast speed. Both machines can produce excellent espresso but rotary machines are more quiet, durable and less likely to break.

The Boiler

The boiler is the one that heats the water to the ideal temperature for extraction. The steam created reaches the portafilter, which contains the espresso coffee grounds. It is then poured into the cup. During this process the steam creates enough pressure to push the grounds of coffee through. This creates a foam on top of the espresso. This is one of the hallmarks of a good espresso.

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

The first espresso machines were steam-based. They utilized a single boiler to make both steam and brew however, the pressure they could create was minimal - two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. The modern espresso coffee machine with milk frother machine was developed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic device with an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans yourself however the pump controls the water flow and pressure. This is an excellent combination of human control and mechanized accuracy.

The Filter

Espresso machines usually have a filter that separates the grounds of the coffee from the hot water. The filter is also an essential component of the machine's temperature control, as it prevents overheating.

A filter also helps with flavor as it allows for a longer flowering phase. This lets the beans release their nuances, and also allows for better extraction.

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

This is where the magic happens, it's what makes espresso taste great. The grouphead, also called the brew head, is where the portafilter (the thing you put the coffee ground into) is located when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds with high pressure. These types of machines are usually less expensive and easier to maintain than pump-driven models. However, they are not as efficient in their ability to provide the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.

In recent years, espresso machines driven by compressed air-pump are becoming increasingly popular. They utilize an air compressor to push hot water across the ground and are more mobile than electric steam-driven espresso machines.