Nine Things That Your Parent Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and amazing filter technology to make the perfect cup of coffee. How does it work exactly?

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

The Head of the Group

The group head is the portafilter you put in when making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure that results from the extraction. There are various kinds of group heads, each with their unique advantages and disadvantages. Some are specifically designed for temperature stability while others are designed to handle pre-infusion. Some are designed to control the lever. Some are a combination, like the E61. This is a preferred choice for baristas since it provides multiple advantages in one package.

As you can see in the image above The group head features several notches where you place your portafilter before twisting it with your hands to lock it in. There is also a gasket of rubber that resides inside the notches, which helps create an airtight seal when you insert your portafilter into the machine. The notches on the head permit an exact placement of the portafilter, which is essential to ensure an even extraction.

The group head not only allows you to insert your portafilter easily but also maintains the temperature at a constant level. This is accomplished by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant for extraction. It is important to realize that even a few degree variation can mean the difference between a good and a great espresso.

The Pump

Unlike manual piston machines, that use a lever to pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure necessary for espresso machine with milk frother extraction. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally more affordable and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to overuse and insufficient cleaning. They also increase the complexity of mechanical systems, which can result in costly prices for even the simplest models.

Some espresso machines remove the pump entirely and use steam pressure to brew espresso. The downside is that the boiler that produces steam also raises the temperature of water to boiling, which can lead to excessive extraction. These machines also have to constantly rebuild their pressure between cups. This takes energy and time.

Many espresso machines make use of either a vibration or rotary pump. A vibration model utilizes an oscillating disk to create pressure, while a rotating model pushes hot water through the ground at a rapid speed. Both types of machine are capable of producing excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler is the one that heats the water to the perfect temperature for extraction. The resulting steam is then transferred to the portafilter which holds the ground espresso and filter coffee machine coffee, and is then funneled down into the cup. During this process, the steam creates pressure to push through the grounds of the coffee. This results in a whipped-up top of the espresso. This is one of the hallmarks of a great espresso.

There are three kinds of espresso makers. They differ in the kind of pump they use and the degree of heat that the brew is. There are many ways to control the brew and the size of cup that can be produced by the machine.

The first espresso machines were steam-based. They had one boiler to make steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure at most. This resulted in the coffee tasting bitter and burnt. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most commonly used espresso machine is a semiautomatic one with an electric pump. These are the images people have when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself while the pump controls the water flow and pressure. This is a perfect solution that combines human control with mechanised accuracy.

The Filter

Espresso machines usually use filters that separate the grounds of the coffee from the hot water. The filter is also a vital element of the machine's temperature control, since it helps to prevent overheating.

A filter also helps with flavor since it allows for a longer flowering period. This allows the beans to release their nuances, and also allows for better extraction.

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

It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead, also referred to as the brew head, is where the portafilter (the thing you put the coffee ground into) sits when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight tank to produce steam, which is then pushed through the grounds at high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal conditions for brewing since they are only operating at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bars.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to force hot water into the ground and are much more mobile than steam-driven electric espresso machines.