20 Questions You Must Always Ask About Machine Espresso Before Buying It

How Does Machine Espresso Work?

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

To make decent espresso machine, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the main difference.

The Head of the Group

As the name implies, the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the extraction. There are numerous kinds of group heads each with its own advantages and disadvantages. Some are designed for stability in temperature, while others are built to handle pre-infusion. Others are made to control the lever. Some contain a variety of features, like the E61, which is the standard choice for many baristas for its ability to provide multiple benefits in a single package.

As you can see from the picture above the group head is fitted with a variety of notches. The portafilter is placed inside these notches, and then turn the head around to secure it. There is also a gasket made from rubber that resides inside the notches and helps to create a seal when you insert your portafilter into the machine. The notches permit precise placement of your portafilter. This is essential for an even extraction.

The group head not only lets you to place your portafilter easily however, it also keeps an even temperature. It does this by cycling hot water through the brew basket, and around the portafilter to ensure that it is always at the right temperature for extraction. It is important to remember that even a few degree deviation can make the difference between a great and a great espresso.

The Pump

In contrast to manual piston machines which rely on a lever to pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure required to extract espresso. The pressure is created by removing tap water from a reservoir and pumping it through a heat exchanger prior to being pumped through the ground coffee inside the group head.

Pumps are generally more affordable and last longer than piston-driven machines. However, both kinds of machines can deteriorate due to overuse and inadequate cleaning. Pumps are also more complex mechanically, which can increase the cost of even the simpler models.

Certain espresso machines remove the pump completely and instead utilize steam pressure to make espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of water to boiling which could lead to excessive extraction. They also have to constantly rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize a vibration or rotary pump, which has a vibration model using a vibrating disc that generates the pressure, and rotating models that push hot water through the grounds under high end espresso machine speed. Both machines can make excellent espresso however rotary machines tend to be quieter, more durable and less likely to fail.

The Boiler

The boiler is what will heat the water to the ideal temperature for extraction. The steam produced reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. The steam generates enough pressure to push the coffee grounds through. This creates a crema on the top of the espresso. This is one of the hallmarks of a great espresso.

There are three different types of espresso machines, each with distinct pumps and brew temperature. There are also different ways that the brew may be controlled and the size of the cup the maker can create.

The earliest espresso machines were steam type. The first decent espresso machine machines were steam-type machines. This resulted in the coffee tasting bitter and burnt. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most common espresso maker is a semiautomatic machine that has an electric pump. When people think of commercial espresso machine machines, they envision these machines. With a semi-automatic espresso machine, you must 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 touch and mechanized accuracy.

The Filter

Typically, espresso machines utilize filters to separate the grounds of the coffee as they go through the hot water. The filter is also an important element of the temperature control system since it helps prevent the machine from overheating.

Filters also aid in flavor since it allows for the beans to flower for a longer period of time. This allows the beans to release their flavor and gives an opportunity to improve extraction.

However, it is important to keep in mind that even a great filter can result in a poor cup of coffee, since the quality of the beans and extraction are vital.

This is where the magic happens, it's what makes espresso taste good. The grouphead, often referred to as the brew head, is where the portafilter (the device you put the ground coffee into) is placed when you're making espresso.

Steam-driven espresso machines use hot water that is heated in an airtight container to produce steam. The steam then pushes hot water through grounds of coffee under high pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. They are however limited to create the ideal conditions for brewing since 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 utilize an air compressor to push hot water across the ground, and are more mobile than electric steam-driven espresso machines.