How Does Machine Espresso Work?

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

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

The Head of the Group

The group head is the portafilter you put in when making espresso. It disperses the water into the portafilter and controls the pressure of the extraction. There are various kinds of group head, each with their particular advantages and drawbacks. Some are designed to provide stability of temperature while others are specifically designed to handle pre-infusion. Others are made to control the lever. Some have a combination, like the E61. This is a preferred choice for baristas as it provides a variety of advantages in a single package.

As you can see in the image above, the group head has many notches in which you can put your portafilter, then twist it by hand to lock it in. A gasket made of rubber is positioned inside the notches, which helps create a seal as you insert your portafilter. The notches on the head permit a precise location of the portafilter which is vital for a consistent extraction.

The group head does not just allow you to place your portafilter easily but also maintains the temperature at a constant level. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right for extraction. It is important to note that even a tiny difference can make the difference between a decent and a excellent espresso.

The Pump

The motorized pumps used in espresso machines that rotate provide the nine atmospheric bars of pressure required for espresso extraction. This is different from manually operated piston machines that employ levers. The pressure is created by removing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.

Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to overuse and inadequate cleaning. They also create mechanical complexity and can lead to costly prices for even the simplest models.

Some espresso machines can eliminate the pump completely and instead make use of steam pressure to make espresso. The downside is that the same boiler that produces steam also raises the temperature of the water to the point of boiling and can result in over-extraction. These machines also have to constantly rebuild their pressure in between cups. This requires energy and time.

Many espresso machines employ either a rotary or vibration pump, Machine Espresso which is a vibration model using a vibrating disc to generate the pressure, and rotating models that push hot water through the grounds at high speed. Both machines can make excellent espresso, however rotary machines are more stable, Machine Espresso quieter and less likely to break down.

The Boiler

The boiler heats the water to the right temperature for extraction. The resultant steam then reaches the portafilter containing the ground espresso coffee espresso machines, and is then pumped into the cup. The steam causes enough pressure to push the grounds of coffee through. This results in a crema on top of the espresso. This is one of the hallmarks of a great espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and how hot the coffee is. There are various ways to control the brew and the size of the cup that can be produced by the machine.

The first espresso machines were steam types. The earliest espresso machines were steam types. The coffee tasted bitter and burned. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most commonly used espresso machine is a semiautomatic with an electric pump. These are the things people think of when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own The pump, however, regulates the flow of water and pressure. This is a great compromise between the human touch and mechanized consistency.

The Filter

Typically, espresso machines have filters to separate the grounds of the coffee as they go through the hot water. The filter is also a vital component of the temperature control system, because it stops the machine from overheating.

It also enhances flavor as a filter lets you enjoy a longer bloom phase. This helps the beans release their flavor and gives the chance for better extraction.

However it is crucial to keep in mind that even a high-quality filter can make a terrible cup of coffee, coffee Espresso machine because the quality of the beans and extraction is essential.

This is where the magic happens, it's the thing that makes an espresso really taste good. The grouphead (also called the brewhead) is where you put the portafilter, which is the thingy which you put the grounds of your coffee into while making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight container to create steam. The steam then pushes hot water into the grounds of coffee under high pressure. They are less expensive and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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