How Does Machine Espresso Work?
Machine espresso uses precision pressure and mind-blowing filter technology to create the perfect cup of coffee. How does it work exactly?
To make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However it is the pressure that makes the main difference.
The Head of the Group
The group head is the portafilter that you place in the espresso maker when making it. It disperses water in the portafilter and regulates the pressure of the extraction. There are a variety of group heads, each with its own advantages and disadvantages. Some are specifically designed for the stability of temperature while some are built to handle pre-infusion. Others are made to control the lever. Some include a combination such as the E61. This is a very popular choice for baristas as it provides a variety of advantages in one package.
As you can see in the above image The group head features several notches to place your portafilter before twisting it with your hands to secure it. A rubber gasket is located in the notches to make a seal when you insert your portafilter. The notches permit precise placement of the portafilter. This is essential for a consistent extraction.
In addition to allowing you easily connect your portafilter, the group head is responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew container and around the portafilter, making sure that it is always at the right temperature to extract. It is crucial to keep in mind that even a few degree deviation can make the difference between a decent and a great espresso.
The Pump
The motorized pumps used in espresso coffee machine for home machines rotary provide nine atmospheric bars of pressure required to extract espresso. This is different from manual piston machines which use a lever. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.
Pumps are generally less expensive than piston-driven machines, and tend to last longer, although both types of machines could become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase prices of even simple models.
Some espresso machines make use of steam pressure instead of a pump for brewing espresso. The drawback of this is that the boiler that produces steam also raises the temperature of water until it reaches boiling and can result in excessive extraction. The machines must also continually rebuild their pressure between cups. This takes energy and time.
Many espresso machines make use of either a vibration or rotary pump. A vibration model makes use of a vibrating disk to generate pressure, whereas the rotary model pushes hot water through the ground at a high speed. Both types of machine can make a great espresso, however rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the one that will heat the water to the right temperature to extract. The steam produced reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then poured into the cup. The steam creates enough pressure to push the coffee grounds through. This results in a layer of crema that is then poured over. This is a sign of a great espresso.
There are three types of espresso machines, each having different pumps and brew temperature. There are a variety of ways in which the brew can be controlled, as well as the dimensions of the cup the machine is capable of making.
The earliest espresso machines were steam types. The first espresso machines were steam types. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was created by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most well-known espresso machine is a semiautomatic with an electric pump. These are the things people think of when they imagine an espresso machine. With a semi-automatic machine, you grind the beans and then tamp them yourself but the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized quality.
The Filter
Espresso machines typically have a filter that separates the coffee grounds from the hot water. The filter is also an important part of the temperature control system because it stops the machine from overheating.
It also aids in flavor, as it allows for a longer bloom phase. This allows beans to let their nuances out and provides an opportunity for a better extraction.
It is important bean to cup espresso machines remember that even the best espresso machine filter can result in a bad cup of coffee. The quality of the beans, and the extraction process, remain vital.
It's here that the magic happens. This is the reason why espresso tastes so delicious. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy that you put the grounds of coffee into while making espresso.
Steam-driven espresso machines use hot water heated in an airtight container to make steam. The steam then pushes hot water into the grounds of coffee at high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. However, they are limited in their capacity to create the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure. However, 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 the hot water through the grounds and are more portable than steam-driven electric machines.