10 Things That Your Family Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the perfect cup of coffee. How does it work exactly?

To make an espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.

The Group Head

As the name suggests the group head is where you put your portafilter in when making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure of the resulting extraction. There are several different types of group heads each with its own advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. Some include a mix of features, like the E61, which is to be the most popular among baristas due to its ability to offer multiple benefits in one package.

As you can see in the picture above the group head is fitted with several notches. The portafilter is placed into these notches and twist the head to lock it. There is also a gasket made from rubber which is located inside the notches to help create a seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is crucial to ensure an accurate extraction.

In addition to allowing you to easily connect your portafilter, the group head is responsible to maintain an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter, making sure that it is always at the right temperature for extraction. This is vital, because even a few degrees can be the difference between a good and great espresso.

The Pump

Unlike manual piston machines, that use a lever to pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure required for espresso extraction. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically more affordable and last longer than piston-driven machines. However, both kinds of machines can degrade due to overuse and poor cleaning. Pumps are also more complicated mechanically, which could increase prices of even most basic models.

Certain espresso machines eliminate the pump completely and utilize steam pressure to make espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of the water until it reaches boiling, which can lead to over-extraction. The machines also need to constantly rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines utilize either a vibration or rotary pump. A vibration model employs an oscillating disk to create pressure, while the rotary model pushes hot water through the ground at a fast speed. Both machines can produce excellent espresso, but rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler makes the water warm to the perfect temperature for extraction. The steam produced reaches the portafilter, which contains the espresso coffee grounds. It is then pumped into the cup. In this process, the steam creates pressure to push through the coffee grounds. This produces a layer of crema that is then poured over. This is a sign of a good espresso.

There are three types of espresso makers, which differ in the type of pump they employ and the degree of heat that the espresso is. There are a variety of ways in which the brew can be controlled, as well as the dimensions of the cup the machine is capable of making.

The first espresso machines were steam types. They used one boiler to create both steam and brew, but the pressure they could produce was not very high - two bars of atmospheric pressure at the most. The coffee tasted bitter and burned. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semiautomatic machine that has an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans on your own, but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanised consistency.

The Filter

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

It also aids in flavor as a filter allows for a longer bloom time. This allows the beans to release their flavor and improves extraction.

However it is crucial to remember that even a high-quality filter could result in a bad cup of coffee, since the quality espresso machine of the beans and extraction is still vital.

It's here that the magic happens. This is what makes espresso taste so delicious. The grouphead (also called the brewhead) is where you place the portafilter, the thingy used to place the grounds of your coffee into when making espresso.

Steam-driven espresso coffee maker machines use hot water that is heated in an airtight vessel to create steam. The steam then pushes hot water through the coffee grounds under high pressure. These types of machines tend to be cheaper and easier to maintain than pump-driven models. They are however limited for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, espresso machines powered by a compressed air compressor have become increasingly popular. They utilize an air compressor to force hot water through the ground and are much more mobile than steam-driven electric espresso machines.