How Does Machine Espresso Work?

Machine espresso uses precision pressure and amazing filter technology to make the perfect cup of coffee. What exactly is it?

In order to make espresso, hot water is pushed under pressure through finely ground coffee and espresso machine. The process is similar to making drip coffee but the major difference is in the pressure.

The Group Head

The group head is the portafilter that you put in when making espresso. It is responsible for dispersing water into the portafilter and controlling the pressure that results from the extraction. There are many different kinds of group head, each with their particular advantages and drawbacks. Some are focused on temperature stability, while others on pre-infusion options, and others are designed to control the lever. Some are a combination, such as the E61. This is a very popular choice for baristas because it offers multiple advantages in a single package.

As you can see in the image above the group head is fitted with a variety of notches. It is possible to place your portafilter inside these notches, and then twist the head to lock it. A gasket made of rubber is placed within the notches to create a seal when you insert your portafilter. The notches on the head permit an exact placement of the portafilter, which is vital for dual Boiler espresso machine an even extraction.

Aside from allowing you to easily place your portafilter in, the group head is also responsible to ensure that the temperature remains even. This is achieved by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is always at the right level to extract the coffee. It is important to remember that even a tiny differences can make the distinction between a good and a great italian espresso machines.

The Pump

In contrast to piston machines that are manually operated, which rely on a lever to pressurize water, Rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure needed to extract espresso. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger before being shot through the ground coffee in the group head.

Pumps are typically less expensive than piston-driven machines and tend to last longer, however both types of machines could be damaged by excessive use and inadequate cleaning. They also increase the complexity of mechanical systems and can lead to a high price tag on even the most basic models.

Certain espresso machines utilize steam pressure instead of a pump for brewing espresso. This can cause over-extraction because the boiler that produces steam also causes the water to boil. The machines also need to continuously rebuild their pressure between cups. This takes energy and time.

Many espresso machines utilize a vibration or rotary pump, with a vibrating model that uses a vibrating disc to generate the pressure and rotating models that push hot water through the grounds at high speed. Both types of machines can produce an excellent espresso, however the rotary models are quieter and more durable than vibration pumps.

The Boiler

The Dual Boiler Espresso Machine is the part which heats the water to the optimal temperature for extraction. The steam that is produced reaches the portafilter which holds ground espresso beans and is then pumped into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This results in a whipped-up top of the espresso. This is a sign of a great espresso.

There are three different types of espresso machines, each having different pumps and brew temperature. There are different ways in which the brew could be controlled as well as the size of the cup that the maker can create.

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

The most popular espresso machine is a semiautomatic that has an electric pump. When people think of espresso machines, they think of these machines. Semi-automatic machines require you to grind and tamp your beans yourself The pump, however, regulates the flow of water and pressure. This is a fantastic compromise between human control and mechanised reliability.

The Filter

Typically, espresso machines use a filter to separate out the grounds of coffee when they pass through the hot water. The filter is also a crucial element of the temperature control system as it prevents the machine from overheating.

It also helps with flavor as a filter allows for a more prolonged bloom time. This helps the beans 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, Dual boiler espresso machine are still crucial.

This is where the magic happens, and it's what makes pro espresso machine taste great. The grouphead, also referred to as the brewhead, is where the portafilter (the device you put the coffee ground into) is placed when making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to create steam. The steam then pushes hot water through grounds of coffee at high pressure. These machines are cheaper and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the ideal brewing conditions, since they operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.

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