Machine Espresso: The Ugly Truth About Machine Espresso

How Does Machine Espresso Work?

The machine espresso uses precise pressure, as well as a filter technology that is mind-blowing to create the coffee you love. What exactly is it that makes it work?

Espresso is created by forcing hot water under pressure through finely-ground coffee machines espresso. The process is similar to making drip coffee. However, the pressure is the primary difference.

The Head of the Group

The name implies, the group head is where you place your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure that results from the extraction. There are many different types of group heads each with its own advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion capabilities, while others are designed to control the lever. There are even some that contain a variety of features, like the E61 that is the standard choice for many baristas for its ability to offer multiple perks in one package.

As you can see in the image above, the group head is fitted with a variety of notches. The portafilter is placed into these notches and twist the head to lock it. There is also a gasket of rubber that resides inside the notches and helps create the seal when you insert your portafilter into the machine. The notches permit an exact placement of the portafilter. This is crucial for a consistent extraction.

Apart from allowing you effortlessly insert your portafilter the group head is also responsible for maintaining a consistent temperature. It does this by cycling hot water through the brew container and around the portafilter to ensure that it's always at the right temperature to extract. It is important to realize that even a few degree difference can make the difference between a great and a great espresso.

The Pump

Unlike manual piston machines, which use a lever to pressurize water, Rotary espresso machines rely on motorized pumps to deliver the nine atmospheric bars of pressure required to extract espresso. This pressure is built up 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. However, both types of machines could degrade with overuse and insufficient cleaning. Pumps are also more complicated mechanically, which can increase the cost of even the most basic models.

Some espresso machines employ steam pressure instead of a pump to brew espresso. This can lead to over-extraction as the boiler that makes steam also heats the water to boil. They also have to constantly rebuild their pressure between cups. This takes energy and time.

A large majority of best espresso machine machines employ either a vibration or rotary pump. A vibration model employs an oscillating disk to create pressure, while a circular model pushes hot liquid through the ground at high speed. Both machines can make excellent espresso, however rotary machines are quieter, more durable and less likely to break down.

The Boiler

The boiler is the component that heats the water to the optimal temperature for extraction. The steam that is produced reaches the portafilter containing the ground espresso coffee, and is then pumped down into the cup. During this process, steam creates pressure to push through the grounds of the coffee. This creates a crema on top of the espresso. This is the hallmark of a good automatic espresso machine.

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

The first espresso machines were steam-based. They employed only one boiler to make steam and brew, however, the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was created by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso coffee machine with milk frother maker is a semiautomatic machine with an electric pump. These are the images people have when they think of an espresso maker. With a semi-automatic espresso machine, you need to grind the beans and then tamp them by hand. The pump controls the flow of water and pressure. This is a great combination of human control and mechanized accuracy.

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from hot water. The filter is also a vital part of the temperature control system because it stops the machine from overheating.

It also aids in flavor, as it allows for a more prolonged bloom phase. This allows the beans to release their nuances, and improves extraction.

However, it is important to keep in mind that even a high-quality filter can make a terrible cup of coffee as the quality of the beans and extraction are vital.

This is where the magic happens, it's the thing that makes an espresso really taste good. The grouphead, sometimes referred to as the brewhead, is where the portafilter (the container you place the coffee grounds into) is located when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight container to create steam, which is then pushed through the grounds at a high pressure. These kinds of machines are usually cheaper and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air-pump-driven espresso machines have become more popular. They use an air compressor to force hot water into the grounds and are much more portable than steam-driven electric machines.