9 Lessons Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and incredible filter technology to produce the coffee we love. How does it work exactly?

To make espresso hot water is pushed under pressure through finely ground coffee and espresso machine. The process is similar to making drip coffee. However, the pressure is the major difference.

The Group Head

The group head is the portafilter is inserted when you are making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are several different types of group head, each with their particular advantages and disadvantages. Some focus on temperature stability, whereas others on pre-infusion features, and others are designed to control the lever. There are even some that include a mix of features, like the E61, which is the most popular choice among baristas due to its ability to provide multiple benefits in a single package.

As you can see in the photo above the group head is made up of numerous notches that you can place your portafilter and twist it by hand to lock it in. A gasket made of rubber is positioned inside the notches to help create a seal while you insert your portafilter. The notches on the head allow for a precise position of the portafilter which is essential to ensure an efficient extraction.

Aside from allowing you to easily connect your portafilter, the group head is responsible to maintain an even temperature. This is done 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 note that even a small variation can mean the difference between a decent and a excellent italian espresso machine.

The Pump

In contrast to manual piston machines which rely on a lever to pressurize water, rotating espresso machines rely upon motorized pumps to supply the nine atmospheric bars of pressure required for espresso extraction. The pressure is created 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 can deteriorate due to excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can increase the price of even the most basic models.

Some espresso machines make use of steam pressure instead of a pump for brewing espresso. The downside is that the boiler that produces steam also increases the temperature of the water until it reaches boiling which can cause over-extraction. They also have to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize a vibration or rotary pump, which has a vibration model that uses a vibrating disc that generates the pressure and a rotary model pushing hot water through the grounds under high speed. Both machines can make great espresso but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the element which heats the water to the optimal temperature to extract. The steam that is created reaches the portafilter, which is the container that holds the espresso coffee grounds. The steam is then channeled into the cup. The steam creates pressure and pushes through the grounds of the coffee. This results in a layer crema that is then poured over. This is a sign of a good espresso.

There are three types of espresso machines, each having distinct pumps and the temperature of the brew. There are also different ways in which the brew could be controlled, as well as the size of the cup the machine is capable of making.

The first compact espresso machine machines were steam-type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine you must grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is an excellent compromise between human touch and the mechanised quality.

The Filter

Espresso machines typically use a filter that separates the grounds of the coffee from the hot water. The filter is also a crucial component of the temperature control system as it prevents the machine from overheating.

A filter also helps with flavor because it allows for a longer flowering period. This lets the beans let their nuances out, and allows for a better extraction.

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

This is where the magic happens, and it's what makes espresso taste great. The grouphead, sometimes called the brew head, is the place where the portafilter (the container you place the ground coffee in) is placed when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds under high pressure. These kinds of machines are typically less expensive and easier to maintain than pump-driven models. They are however limited for creating the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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