Do Not Believe In These "Trends" About Machine Espresso

How Does Machine Espresso Work?

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

To make espresso, hot water is pushed under 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 name implies, the group head is where you insert your portafilter when brewing espresso. It disperses water into the portafilter and regulates the pressure of extraction. There are a variety of group heads, each with its own advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are made to control the lever. Some have a combination, like the E61. This is a favorite among baristas since it provides multiple benefits in one package.

As you can see from the picture above, the group head is equipped with several notches. You place your portafilter inside these notches, and then turn the head around to secure it. There is also a gasket of rubber which is located inside the notches, which helps create a seal when you insert your portafilter into the machine. The notches permit precise placement of your portafilter. This is crucial to ensure an efficient extraction.

The group head does not just allow you to place your portafilter easily however it also keeps the temperature at a constant level. This is done by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is constant for extraction. This is vital, because even a small difference in temperature can mean the difference between excellent and great espresso.

The Pump

In contrast to manual piston machines that use a lever to pressurize water, the rotary espresso machines use motorized pumps that provide the nine atmospheric bars of pressure that are required to extract espresso. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer, although both types of machines may degrade with overuse and insufficient cleaning. They also increase the complexity of mechanical systems that can lead to costly prices for even the most basic models.

Certain espresso machines do away with the pump completely and instead employ steam pressure to create espresso. This can result in over-extraction because the boiler that produces steam also causes the water to boil. Additionally these machines are often required to rebuild their pressure between cups, which takes time and energy.

Many espresso machines employ the rotary or vibration pump, which is a vibration model that uses a vibrating disc that generates the pressure and rotating models that push hot water through the grounds under high speed. Both types of machine can make a great espresso, but rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the part which heats the water to the optimal temperature to extract. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee, and is then funneled down into the cup. During this process the steam causes enough pressure to push the grounds of coffee through. This creates a foam on top of the espresso. This is one of the hallmarks of a great espresso.

There are three types of espresso makers, which differ in the type of pump they use and how hot the coffee is. There are also different ways in which the brew can be controlled and the size of the cup the machine is capable of making.

The first espresso machines were steam-type. They utilized one boiler to make both steam and brew however, the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso maker is a semi-automatic machine that has an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic espresso machine, you have to grind the beans and tamp them by hand, but the pump is able to regulate the flow of water and pressure. This is an excellent combination of human control and mechanized accuracy.

The Filter

Typically, espresso machines utilize a filter to separate out the grounds of the coffee as they go through the hot water. The filter is also a vital part of the machine's temperature control, as it prevents overheating.

It also helps with flavor, since a filter allows for a more prolonged bloom time. This allows the beans to release their nuances, and also allows for better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans and the extraction process, remain vital.

This is where the magic happens, it's what makes an espresso really taste good. The grouphead (also known as the brewhead) is where you place the portafilter - the thingy used to place the coffee grounds in, when making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to create steam. Steam then pushes the hot water through the grounds under high pressure. best espresso machine of machines tend to be less expensive and simpler to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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