How Does Machine Espresso Work?

The machine espresso makes use of precision pressure, and a filtering technology that is amazing to make the coffee you enjoy. How exactly does it work?

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 you place in the espresso maker when making it. It disperses water into the portafilter, and then regulates the pressure of the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some focus on temperature stability, whereas others on pre-infusion capabilities, while others are designed to control the lever. There are some that contain a variety of features, such as the E61 one, which is the classic choice among many baristas due to its capacity to offer multiple benefits in a single package.

As you can see in the above image the group head comes with numerous notches that you can place your portafilter before twisting it with your hands to secure it. There is also a gasket of rubber that resides inside the notches and helps to create an airtight seal after inserting your portafilter into the machine. The notches allow for precise placement of your portafilter. This is essential for an accurate extraction.

The group head does not just allow you to put in your portafilter easily, but it also maintains the temperature at a constant level. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right to extract the coffee. It is important to remember that even a slight variation can mean the difference between a great and a excellent espresso.

The Pump

Unlike manual piston machines, which rely on a lever to pressurize water, Rotary espresso machines rely on motorized pumps to supply the nine atmospheric bars of pressure required to extract espresso. The pressure is created by drawing tap water from a reservoir, and pumping it through a heat exchanger prior being shot through the ground coffee inside the group head.

Pumps tend to be less expensive and last for longer than piston-driven machines. However, both kinds of machines may degrade due to overuse and insufficient cleaning. They also add mechanical complexity that can lead to the cost of even the simplest models.

Certain espresso machines remove the pump entirely and use steam pressure to brew espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of water until it reaches boiling which could lead to over-extraction. These machines also have to constantly rebuild their pressure between cups. This requires energy and time.

A majority of espresso machines use an rotary or vibrating pump, with a vibrating model using a rotating disc that generates the pressure and the rotary model pushing hot water through the grounds at high speed. Both machines can make great espresso, however rotary machines are quieter, more durable and less likely to break.

The Boiler

The boiler is the part that heats water to an ideal temperature for extraction. The steam that is produced will eventually reach the portafilter, which contains the espresso coffee grounds. The steam is then channeled into the cup. During this process the steam is able to create enough pressure to push the grounds of the coffee through. This creates a layer crema that is then poured over. This is the hallmark of a great espresso.

There are three kinds of espresso machines, each having a different type of pump and brew temperature. There are a variety of ways to control the brew and the size of cup that can be produced by the machine.

The first professional espresso machine for home machines were steam-types. The first espresso machines were steam-type machines. The coffee tasted bitter and burnt. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most popular espresso machine is a semiautomatic one with an electric pump. These are the things people think of when they think of an espresso machine. If you have a semi-automatic machine you have to grind the beans and tamp them by hand. The pump provides regulated water flow and pressure. This is an excellent compromise between human touch and the mechanized quality.

The Filter

mini espresso machine (use kizkiuz.com here) machines typically use filters that separate the grounds of the coffee from the hot water. The filter is also an essential part of the machine's temperature control, since it helps to prevent overheating.

A filter can also help with flavor because it allows for a longer flowering period. This lets the beans release their flavor and also allows for better extraction.

It is important to remember that even the finest filter can make a bad cup of coffee. The quality of the beans, and the extraction, are still very important.

It's in this area that the magic happens. This is the reason why espresso tastes so good. The grouphead, sometimes called the brew head, is the place where the portafilter (the thing you put the coffee grounds into) is located when you're making espresso.

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

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