How Does Machine Espresso Work?

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

In order to make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee, however the main difference lies in the pressure.

The Head of the Group

The group head is the portafilter you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter and then controlling the pressure of the resulting extraction. There are many different kinds of group head each with its unique advantages and disadvantages. Some are specifically designed for the stability of temperature while some are designed to handle pre-infusion. Others are built to control the lever. Some include a combination like the E61. This is a very popular choice for baristas because it offers multiple advantages in one package.

As you can see in the photo above the group head is made up of several notches where you place your portafilter before twisting it manually to lock it in. There is also a gasket of rubber that resides inside the notches, which helps create the seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is essential for an efficient extraction.

Apart from allowing you easily connect your portafilter, the group head is also responsible for maintaining an even temperature. It does this by cycling hot water through the brew basket and around the portafilter, ensuring that it's always at the correct temperature to extract. It is important to remember that even a tiny variation can mean the difference between a good and great espresso.

The Pump

In contrast to manual piston machines which rely on a lever that pressurize water, rotating espresso machines rely upon motorized pumps to deliver the nine atmospheric bars of pressure that are required to extract espresso. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive and last longer than piston-driven machines. However, both kinds of machines may degrade because of frequent use and insufficient cleaning. They also make mechanically complex that can lead to the cost of even the most basic models.

Some cafe espresso machine machines make use of steam pressure instead of a pump for brewing espresso. This can lead to over-extraction as the boiler that produces steam also warms the water to boil. In addition, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines make use of the rotary or espresso machine With milk frother vibration pump, with a vibration model using a rotating disc that generates the pressure and a rotary model pushing hot water through the grounds at high speed. Both machines can make great espresso but rotary machines are more stable, quieter and less likely to fail.

The Boiler

The boiler is the component that heats water to an ideal temperature for extraction. The steam that is produced is then directed to the portafilter, which is the container that holds the espresso coffee grounds. It is then poured into the cup. The steam is able to create enough pressure to push the grounds of coffee 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 a different type of pump and the temperature of the brew. There are a variety of ways in which the brew can be controlled and the size of the cup the machine can produce.

The first espresso machines were steam-types. The first espresso machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was designed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso machine is a semiautomatic model with an electric pump. These are the images people have when they think of an espresso machine. If you have a semi-automatic machine you must grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a perfect combination of human control and mechanised accuracy.

The Filter

Typically, espresso machines employ a filter to separate out the grounds of coffee as they move through the hot water. The filter is also a vital part of the machine's temperature control, since it helps to prevent overheating.

A filter also improves flavor since it allows for an extended flowering time. This helps the beans release their flavors and provides an opportunity for better extraction.

However it is crucial to remember that even a top filter can result in a poor cup of coffee, because the quality of the beans and extraction is crucial.

It's here that the magic takes place. This is the reason why espresso tastes so delicious. The grouphead, sometimes called the brewhead, is where the portafilter (the thing you put the coffee grounds into) is placed when you're making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds at a high pressure. These machines are less expensive and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

In recent years, espresso machine with milk frother machines driven by compressed air-pump have become increasingly popular. They use an air compressor to force hot water through the grounds, and are far more portable than steam-driven electric machines.