Consuelo Burchfield

How Does Machine Espresso Work?

Machine espresso coffee machine for home employs precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it?

Espresso is made by forcing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However the pressure is the major difference.

The Head of the Group

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter before controlling the pressure that results from the extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some are specifically designed for stability in temperature, while others are built to handle pre-infusion. Some are designed to control the lever. Some come with a range of features, such as the E61, which is the most popular choice among baristas because of its ability to offer multiple perks in a single package.

As you can see from the above photo, the group head is equipped with several notches. The portafilter is placed inside these notches, and then twist the head to secure it. A rubber gasket is located in the notches to create a seal while you insert your portafilter. The notches on the head allow for an exact positioning of the portafilter which is vital for an even extraction.

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

The Pump

In contrast to piston machines that are manually operated, that use a lever to pressurize water, rotating espresso machines rely upon motorized pumps to provide the nine atmospheric bars of pressure needed to extract espresso. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior to it is shot through the ground coffee inside the group head.

Pumps tend to be cheaper than piston-driven models, and they tend to last longer, however both types of machine can be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, which can raise the cost of even the most basic models.

Certain espresso machines eliminate the pump completely and use steam pressure to brew espresso. The drawback is that the same boiler that produces steam also increases the temperature of the water to boiling, which can lead to over-extraction. The machines also need to continuously rebuild their pressure between cups. This requires energy and time.

Many cafe espresso machine machines make use of the rotary or vibration pump. A vibration model utilizes the vibrating disk to create pressure, whereas a circular model pushes hot liquid through the ground at high speed. Both machines can make excellent mini espresso maker, however rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler makes the water warm to a temperature that is ideal for extraction. The steam that is produced reaches the portafilter that contains the ground espresso coffee, and is then funneled down into the cup. The steam causes enough pressure to push the grounds of the coffee through. This results in a layer crema that is then poured over. This is one of the hallmarks of a good espresso.

There are three types of espresso machines, each with different pumps and brew temperature. There are various ways that the brew may be controlled, as well as the dimensions of the cup the machine can produce.

The first espresso machines were steam types. The first espresso machines were steam-type machines. The coffee tasted bitter and burned. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans by yourself while the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

Typically, espresso machines utilize filters that separate the grounds of coffee as they move through the hot water. The filter is also an important component of the temperature control system, as it keeps the machine from overheating.

It also helps with flavor, as a filter can allow for a longer bloom phase. This allows beans to let their nuances out and provides an opportunity for a better extraction.

It is important to keep in mind that even the best 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 what makes an espresso maker barista really taste great. The grouphead, often called the brew head, is where the portafilter (the thingy you put the ground coffee for espresso machine in) is located when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to produce steam. The steam then moves hot water through the grounds of coffee under high pressure. These machines are cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to create the perfect conditions for brewing, as they only operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.

In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They utilize an air compressor to push hot water through the grounds and are much more portable than electric steam-driven machines.