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?

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

The Group Head

The name implies the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure of the resulting extraction. There are a variety of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, others on pre-infusion capabilities, while others are designed to control the lever. Some contain a variety of features, such as the E61 that is to be the most popular among baristas because of its ability to provide multiple benefits in a single package.

As you can see in the image above the head of the group is equipped with several notches. You place your portafilter in these notches, then twist the head to secure it. A rubber gasket is located within the notches to create a seal while you insert your portafilter. The notches on the head permit an exact positioning of the portafilter which is vital to ensure a consistent extraction.

The group head not only lets the portafilter to be inserted easily however it also keeps the same temperature. It does this by cycling hot water through the brew container and around the portafilter to ensure that it is always at the right temperature for extraction. This is important, as just a few degrees could mean the difference between good and excellent mini espresso machine.

The Pump

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

Pumps are typically less expensive and last for longer than piston-driven machines. However, both types of machines may degrade because of excessive use and insufficient cleaning. Pumps are also more complex mechanically, and can add to the price of even the most basic models.

Some espresso machines use steam pressure instead of a pump in order to brew espresso. The disadvantage of this is that the same boiler that produces steam also increases the temperature of water until it reaches boiling, which can lead to over-extraction. In addition the machines often have to restore their pressure between cups, which takes time and energy.

A large majority of espresso machines employ a rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, whereas a rotary model pushes hot water through the ground at high speed. Both machines can produce excellent espresso however rotary machines tend to be more stable, quieter and less likely to break down.

The Boiler

The boiler is the part that heats water to the optimal temperature to extract. The steam created reaches the portafilter, which contains the espresso coffee grounds. It is then poured into the cup. During this process the steam causes enough pressure to push the grounds of the coffee through. This creates a foam on the top of the espresso. This is a hallmark of a great espresso.

There are three types of espresso machines, each having different types of pumps and brew temperature. There are different ways to control the brew and the size of the cup that can be made by the machine.

The first espresso machines were steam-types. They utilized only one boiler to make both steam and brew however the pressure they were able to create was minimal - two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most popular espresso maker is a semiautomatic machine that has an electric pump. These are the things people think of when they think of an espresso machine. With a semi-automatic machine you have to grind the beans and then tamp them by hand. The pump is able to regulate the flow of water and pressure. This is a great compromise between the human touch and the mechanized consistency.

The Filter

Typically, espresso machines utilize filters to separate the coffee grounds as they pass through the hot water. The filter is also an essential component of the machine's temp control, as it prevents overheating.

A filter also improves flavor because it allows for a longer flowering phase. This allows the beans to release their nuances and gives an opportunity for buy espresso machines better extraction.

It is important to keep in mind that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction process, are still very important.

This is where the magic happens. It's what makes espresso taste good. The grouphead (also known as the brewhead) is where you put the portafilter, the device that you use to put the grounds of coffee into while making buy espresso makers espresso machine coffee machines - Imoodle noted,.

Steam-driven espresso machines use hot water that is heated inside an airtight container to make steam. The steam then pushes hot water into the coffee grounds under high pressure. These kinds of machines are usually less expensive and simpler to maintain than pump-driven models. However, they are not as efficient in their ability to create the ideal brewing conditions, because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, compressed air-pump-driven espresso machines have been gaining popularity. They use an air-compressor to push hot water through the ground and are more mobile than steam-driven electric espresso machines.