How Does Machine Espresso Work?

The machine espresso makes use of precision pressure, and filtering system that is awe-inspiring to create the coffee you love. How exactly does it work?

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

The Group Head

The group head is the portafilter you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter, and controlling the pressure of the resulting extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some are designed to provide the stability of temperature while some are designed to handle pre-infusion. Others are built to control the lever. Some come with a range of features, like the E61 one, which is to be the most popular among baristas due to its ability to offer multiple perks in one package.

As you can see from the above photo the head of the group is fitted with a variety of notches. You can place your portafilter into these notches and twist the head to secure it. There is also a gasket made from rubber that is a part of the notches and helps create a seal when you insert your portafilter into the machine. The notches permit precise placement of the portafilter. This is vital for an even extraction.

The group head not only allows the portafilter to be inserted easily however, it also keeps an even temperature. It does this by circulating hot water through the brew container and around the portafilter, making sure that it is always at the correct temperature for extraction. It is important to note that even a tiny variation can mean the difference between a decent and a great espresso.

The Pump

The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bars of pressure required to extract espresso. This is different from manual piston machines which use levers. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.

Pumps are generally less expensive than piston-driven machines, and tend to last longer, although both types of machines could degrade with overuse and insufficient cleaning. They also increase the complexity of mechanical systems that can lead to an expensive price for even the simplest models.

Certain mini espresso maker machines utilize steam pressure instead of a pump to make espresso. The drawback of this is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling, which can lead to excessive extraction. In addition these machines typically have to restore their pressure between cups, which requires time and energy.

Many espresso machines utilize either a rotary or vibration pump, which is a vibration model using a rotating disc to generate the pressure, and the rotary model pushing hot water through the grounds at high speed. Both models can make a great espresso, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the component which heats the water to the optimal temperature for extraction. The resulting steam reaches the portafilter that contains ground professional espresso maker beans and gets funnelled down into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This results in a whipped-up top of the espresso. This is one of the hallmarks of a good espresso.

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

The first espresso machines were steam types. The earliest Buy espresso machines (www.longisland.com) machines were steam-type machines. This led to the coffee tasting burnt and bitter. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso home machine machine.

The most common espresso machine is a semiautomatic with an electric pump. This is what people envision when they think of an espresso maker. With a semi-automatic machine you need to grind the beans and 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 accuracy.

The Filter

Espresso machines typically use filters that separate the grounds of the coffee from hot water. The filter is also a vital component of the temperature control system since it helps prevent the machine from overheating.

It also aids in flavor, as a filter can allow for a longer bloom time. This allows the beans to release their nuances, and allows for a better extraction.

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

This is where the magic happens, it's the thing that makes an espresso really taste great. The grouphead, sometimes referred to as the brew head, is the place where the portafilter (the device you put the ground coffee in) is located when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to make steam. The steam then pushes hot water through grounds of the coffee under pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. They are however limited to create the perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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 ground and are more mobile than electric steam-driven espresso machines.