The Ugly Truth About Machine Espresso

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and mind-blowing filter technology to create the coffee we love. How exactly does it work?

To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to that of making drip coffee machines espresso. However the pressure is the primary difference.

The Group Head

As the name implies, the group head is where you place your portafilter when brewing espresso. It disperses the water into the portafilter, and then regulates the pressure during the extraction. There are several different types of group head, each with their unique advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are made to control the lever. There are some that contain a variety of features, such as the E61, which is to be the most popular among baristas due to its ability to provide multiple benefits in one package.

As you can see in the above photo, the group head has many notches in which you can place your portafilter and then twist it manually to secure it. A gasket of rubber is situated inside the notches, which helps create a seal as you insert your portafilter. The notches on the head allow for an exact location of the portafilter which is vital for a consistent extraction.

The group head does not just allow you to insert your portafilter easily but also maintains the same temperature. This is done by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant to extract the coffee. It is important to note that even a tiny difference can make the difference between a great and a great espresso machine small.

The Pump

In contrast to piston machines that are manually operated, which use a lever to pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure that are required for espresso extraction. The pressure is created by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically less expensive and last for longer than piston-driven machines. However, both types of machines are susceptible to degrading due to overuse and poor cleaning. Pumps are also more complex mechanically, which could increase the cost of even simplest models.

Certain espresso machines remove the pump completely and instead employ steam pressure to create espresso. The downside is that the same boiler that produces steam also raises the temperature of water to the point of boiling, which can lead to over-extraction. These machines also have to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines (check) utilize an rotary or vibrating pump, with a vibrating model that uses a vibrating disc that generates the pressure, and rotating models that push hot water through the grounds at high speed. Both machines can produce excellent espresso, but rotary machines are more quiet, durable and less likely to fail.

The Boiler

The boiler is the element that heats water to an ideal temperature for extraction. The steam that is created gets to the portafilter which holds the espresso grounds. It is then pumped into the cup. During this process, steam creates pressure that pushes through the grounds of the coffee. This results in a crema on the top of the espresso. This is one of the main characteristics of a great espresso.

There are three different types of espresso machines, each having different pumps and the temperature of the brew. There are also different ways that the brew can be controlled as well as the size of the cup the machine can make.

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

The most popular espresso maker is a semiautomatic machine with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic machine you have to grind the beans and then tamp them by hand, but the pump regulates the flow of water and pressure. This is an excellent compromise between human control and mechanised reliability.

The Filter

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

A filter can also help with flavor because it allows for the beans bean to cup espresso machine flower for a longer period of time. This allows the beans to release their flavor and also allows for better extraction.

It is important to remember that even the finest filter can result in a bad cup of coffee. The quality of the beans, and the extraction process, remain vital.

It's in this area that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead, often referred to as the brew head, is where the portafilter (the container you place the coffee ground into) is located when you're making espresso.

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

In recent years, compressed air pump-driven espresso machines have been gaining popularity. They make use of an air compressor to push hot water through the ground and are much more mobile than electric steam-driven espresso machines.