Nine Things That Your Parent Teach You About Machine Espresso

How Does Machine Espresso Work?

Machine espresso employs precise pressure and mind-blowing filter technology to make the coffee we love. What exactly is it that makes it work?

Espresso is made 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 major difference.

The Group Head

The name implies, the group head is where you place your portafilter when making espresso. It disperses the water into the portafilter, and controls the pressure of the extraction. There are numerous kinds of group heads, each with its own advantages and drawbacks. Some are designed for the stability of temperature while some are built to handle pre-infusion. Others are built to control the lever. Some include a combination like the E61. This is a preferred choice for baristas because it offers multiple advantages in one package.

As you can see in the picture above, the group head is fitted with several notches. The portafilter is placed in these notches and then twist the head to secure it. There is also a rubber gasket which is located inside the notches to help create the seal when you insert your portafilter into the machine. The notches permit an exact placement of the portafilter. This is crucial for an even extraction.

The group head is not just able to allow you to put in your portafilter easily however, it also keeps a constant temperature. This is accomplished by cycling hot water around the portafilter and through the brew-basket, ensuring that the temperature is always at the right level for extraction. This is important because just a few degrees could make the difference between good and great espresso.

The Pump

Motorized pumps in espresso machines rotary provide nine atmospheric bars of pressure required for cafe espresso machine extraction. This is different from manual piston machines that rely on a lever. This pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pushed through the best ground coffee for espresso machine coffee inside the group head.

Pumps tend to be cheaper and last longer than piston-driven machines. However, both kinds of machines can degrade due to overuse and inadequate cleaning. Pumps are also more complicated mechanically, which can increase the cost of even simpler models.

Some espresso machines use steam pressure instead of a pump to make espresso. The drawback is that the boiler that produces steam also raises the temperature of the water to boiling which can cause over-extraction. Additionally these machines are often required to restore their pressure between cups, which requires time and energy.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model makes use of a rotating disk to generate pressure, whereas a circular model pushes hot liquid through the ground at a fast speed. Both types of machine can make a great espresso, however the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is what is used to heat the water to the ideal temperature for extraction. The steam that is produced will eventually reach the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. During this process the steam creates enough pressure to push the coffee grounds through. This results in a crema on the top of the espresso. This is the hallmark of a great espresso.

There are three kinds of espresso makers, and they differ in the kind of pump they use and the degree of heat that the espresso is. There are a variety of ways in which the brew could be controlled and the size of the cup the machine can produce.

The first espresso machines were steam type. They utilized a single boiler to make both steam and brew however the pressure they were able to produce was very low - just two bars of atmospheric pressure, at most. This led to the coffee tasting bitter and burnt. This is the reason why Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

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

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from the hot water. The filter is also a vital part of the machine's temperature control, as it helps prevent overheating.

A filter also improves flavor as it allows for an extended flowering time. This helps the beans to let their nuances out and provides the chance for better extraction.

However, it is important to keep in mind that even a top filter can result in a poor cup of coffee, as the quality of the beans and extraction are essential.

It's here that the magic happens. This is what makes espresso taste so delicious. The grouphead (also known as the brewhead) is where you put the portafilter, the device that you put the grounds of your coffee into when making espresso coffee machines.

Steam-driven espresso machines make use of 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 types of machines tend to be less expensive and simpler to maintain than pump-driven models. However, they are not as efficient in their ability to provide the perfect brewing conditions because they operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bar.

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