How Does Machine Espresso Work?

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

Espresso is made by pushing hot water under pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the primary difference.

The Head of the Group

As the name implies the group head is where you place your portafilter while making espresso. It is responsible for dispersing water into the portafilter before controlling the pressure that results from the extraction. There are a variety of group heads each with distinct advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion features, and others are designed to control the lever. There are also some that include a mix of features, like the E61, which is to be the most popular among baristas due to its ability to offer multiple perks in a single package.

As you can see in the above photo the head of the group is fitted with several notches. You can place your portafilter in these notches, then twist the head to lock it. There is also a gasket made from rubber that resides inside the notches and helps create the seal when you insert your portafilter into the machine. The notches permit the precise placement of the portafilter. This is essential for an even extraction.

In addition to allowing you effortlessly insert your portafilter the group head is responsible for maintaining an even temperature. This is done by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is at the right level for extraction. It is important to note that even a slight deviation can make the difference between a great and a excellent espresso.

The Pump

The motorized pumps used in rotary espresso machines provide the nine atmospheric bars of pressure required for travel espresso maker extraction. This differs from manual piston machines which use a lever. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically cheaper and last longer than piston-driven machines. However, both kinds of machines may degrade because of frequent use and poor cleaning. Pumps are also more complex mechanically, which could increase the cost of even simpler models.

Some espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. This can cause over-extraction because the boiler that produces steam also causes the water to boil. The machines also need to continually rebuild their pressure between cups. This requires energy and time.

A majority of espresso machines use the rotary or vibration pump, with a vibrating model that uses a vibrating disc to create pressure, and an rotary model that pushes hot water through the grounds under high speed. Both machines can make great espresso but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is the part that heats the water to the optimal temperature to extract. The steam produced will eventually reach the portafilter, Espresso Coffee Machine Uk which is the container that holds the espresso coffee grounds. It is then pumped into the cup. In this process, the steam causes pressure to push through the grounds of the coffee. This results in a whipped-up the top of the espresso. This is one of the hallmarks of a great espresso.

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

The first espresso machines were steam type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burnt. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso coffee machine uk (qooh.me blog post) machine.

The most common espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic machine you grind the beans and tamp them by hand. However, the pump provides regulated water flow and pressure. This is a great compromise between the human touch and mechanized accuracy.

The Filter

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

Filters also aid in flavor, as it permits the beans to flower for a longer period of time. This lets the beans release their nuances, and allows for better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans, and the extraction process, remain crucial.

This is where the magic happens, it's the thing that makes espresso taste great. The grouphead, often referred to as the brew head, is the place where the portafilter (the device you put the ground coffee in) sits when you're making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam, which then pushes the hot water through the grounds at a high pressure. These types of machines are typically less expensive and simpler 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, compressed-air-pump-driven espresso machines have been gaining popularity. They use an air compressor to force hot water into the ground and are much more mobile than steam-driven electric espresso machines.