How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the perfect cup of coffee. 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 making drip coffee but the major difference is in the pressure.

The Head of the Group

The group head is the portafilter is inserted when you are making espresso. It disperses the water into the portafilter and regulates the pressure of the extraction. There are a variety of types of group heads each with its own advantages and disadvantages. Some are focused on temperature stability, others on pre-infusion features, and others are designed to control the lever. Some come with a range of features, such as the E61 that is the most popular choice among baristas due to its capacity to offer multiple benefits in one package.

As you can see in the image above The group head features several notches where you put your portafilter, then twist it manually to secure it. There is also a gasket made of rubber that resides inside the notches to help create the seal when you insert your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is essential to ensure an efficient extraction.

Apart from allowing you easily insert your portafilter, the group head is also responsible to maintain an even temperature. It does this by circulating hot water through the brew basket and around the portafilter, ensuring that it is always at the right temperature for extraction. This is crucial, since even a small difference in temperature can make the difference between a excellent and great espresso.

The Pump

In contrast to piston machines that are manually operated, that use a lever to pressurize water, the rotary espresso machines use 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 it is shot through the ground coffee inside the group head.

Pumps are typically less expensive than piston-driven machines, and tend to last longer. However, both types of machines may be damaged by excessive use and inadequate cleaning. They also make mechanically complex that can lead to an expensive price for even the most basic models.

Certain espresso machines utilize steam pressure instead of a pump to brew espresso. The downside is that the same boiler that produces steam also increases the temperature of water to the point of boiling and can result in over-extraction. The machines also need to continually rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize the rotary or vibration pump, with a vibration model using a vibrating disc to create pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines produce great espresso but rotary machines are more stable, quieter and less likely to break down.

The Boiler

The boiler is the part which heats the water to the ideal temperature for extraction. The resulting steam is then transferred to the portafilter which holds ground espresso beans and is then pumped into the cup. The steam creates enough pressure to push the grounds of coffee through. This produces a layer of crema that is then poured over. This is the hallmark of a great espresso.

There are three kinds of espresso machines, each having distinct pumps and the temperature of the brew. There are also different ways that the brew may be controlled as well as the dimensions of the cup the maker can create.

The first professional espresso machine for home machines were steam-types. They used one boiler to create both brew and steam, however the pressure they were able to produce was very low - just two bars of atmospheric pressure at most. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso machine is a semiautomatic model with an electric pump. This is what people envision when they think of an mini espresso maker machine. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the water flow and pressure. This is a perfect compromise between human control and mechanised consistency.

The Filter

best home espresso machine machines usually have filters that separate the coffee grounds from the hot water. The filter is also a crucial element of the temperature control system, as it keeps the machine from overheating.

It also aids in flavor, as it allows for a longer bloom phase. This helps the beans release their nuances and Machine Espresso gives an opportunity to improve extraction.

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

It's here that the magic takes place. This is what makes espresso taste so delicious. The grouphead (also called the brewhead) is where you place the portafilter, the thingy which you put the grounds of your coffee into when making espresso.

In a steam-driven espresso coffee machine for home machine hot water is heated in an airtight container to create steam. This is then pushed through the grounds under high pressure. These types of machines tend to be cheaper and easier to maintain than pump-driven models. However, they are not as efficient in their capacity to create the perfect conditions for brewing, since they operate at 1-1.5 bars of pressure. However, the perfect 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 through the ground. They are also more mobile than steam-driven electric espresso machines espresso machines.