How Do I Explain Machine Espresso To A 5-Year-Old

How Does Machine Espresso Work?

The machine espresso is made using precision pressure, and a filtering system that is awe-inspiring to make the coffee you love. But how exactly does it work?

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

The Group Head

As the name suggests the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure of the resulting extraction. There are a variety of types of group heads each with its own advantages and drawbacks. Some are designed to provide temperature stability while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some come with a combination of both, such as the E61. This is a popular choice among baristas due to the fact that it has multiple advantages in a single package.

As you can see in the image above the group head is made up of many notches in which you can put your portafilter, then twist it by hand to lock it in. A gasket of rubber is situated inside the notches to help make a seal when you insert your portafilter. The notches on the head allow for an exact location of the portafilter which is essential to ensure an even extraction.

Apart from allowing you easily insert your portafilter, the group head is responsible for maintaining a consistent temperature. This is done by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is always at the right level for extraction. This is important, as just a few degrees could make the difference between good and great espresso.

The Pump

The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure required to extract espresso. This is different from manual piston machines which use a lever. The pressure is created by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven machines, and tend to last longer, although both types of machine can get damaged through overuse and lack of cleaning. They also add mechanical complexity that can lead to an expensive price for even the most basic models.

Certain espresso machines do away with the pump completely and instead utilize steam pressure to make espresso. The disadvantage of this is that the boiler that produces steam also increases the temperature of water to the point of boiling which could lead to over-extraction. In addition the machines often have to restore their pressure between cups, which requires time and energy.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model makes use of the vibrating disk to create pressure, while a rotary model pushes hot water through the ground at a rapid speed. Both machines can make great espresso, however rotary machines are quieter, more durable and less likely to break down.

The Boiler

The boiler is the element that heats water to the ideal temperature for extraction. The steam that is produced reaches the portafilter containing the ground espresso and gets funnelled down into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This creates a layer crema that is then poured over. This is one of the hallmarks of a good espresso.

There are three types of espresso makers, and they differ in the type of pump they employ and how hot the brew is. There are many ways to control the brew and the size of the cup that can be made by the machine.

The first espresso machines were steam-type. The earliest espresso machines were steam types. This resulted in the coffee tasting bitter and burnt. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most popular espresso machine is a semiautomatic that has an electric pump. These are the images people have when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans on your own however the pump controls the water flow and pressure. This is a perfect combination of human control and mechanised accuracy.

The Filter

Typically, espresso machines employ a filter to separate out the coffee grounds as they pass through the hot water. The filter is also a crucial part of the temperature control system, as it prevents the machine from overheating.

It also enhances flavor, as a filter can allow for a longer bloom phase. This lets the beans let their nuances out, and allows for better extraction.

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

It's here that the magic takes place. This is what makes espresso taste so good. The grouphead (also called the brewhead) is where you place the portafilter, the thingy which you put the coffee grounds in, when making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to create steam, which then pushes the hot water through the grounds at high pressure. These machines are less expensive and easier for the owner to maintain than pumps-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 get more info machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to force hot water through the ground, and are more mobile than electric steam-driven espresso machines.