10 Facts About Machine Espresso That Make You Feel Instantly A Good Mood
10 Facts About Machine Espresso That Make You Feel Instantly A Good Mood
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How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to create the delicious coffee we enjoy. What exactly is it that makes it work?
To make espresso, hot water is forced under high 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 you insert when brewing espresso. It disperses water in the portafilter, and then controls the pressure of the extraction. There are numerous kinds of group heads each with distinct advantages and disadvantages. Some are specifically designed for temperature stability while others are built to handle pre-infusion. Some are designed to control the lever. Some include a combination such as the E61. This is a very popular choice for baristas because it offers multiple advantages in a single package.
As you can see from the above photo the group head has a number of notches. The portafilter is placed in these notches and then turn the head around to secure it. A gasket made of rubber is positioned inside the notches to help create a seal when you insert your portafilter. The notches on the head allow for an exact positioning of the portafilter which is vital for a consistent extraction.
The group head not only allows you to put in your portafilter easily however it also keeps the same temperature. This is achieved by cycling hot water around the portafilter, and through the brew basin, ensuring that the temperature is at the right level to extract the coffee. This is important, as just a few degrees could make the difference between excellent and great espresso.
The Pump
Unlike manual piston machines, which use a lever to pressurize water, rotating espresso machines rely upon motorized pumps to provide the nine atmospheric bars of pressure necessary to extract espresso. The pressure builds by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pushed through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines, and tend to last longer. However, both types of machine can get damaged through overuse and lack of cleaning. They also add mechanical complexity that can lead to costly prices for even the simplest models.
Some espresso machines make use of steam pressure instead of a pump to brew espresso. The downside is that the boiler that produces steam also increases the temperature of water to boiling, which can lead to over-extraction. In addition these machines are often required to restore their pressure between cups, which requires time and energy.
A large majority of espresso machines employ the rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, whereas a circular model pushes hot liquid through the ground at a rapid speed. Both machines can make great espresso however rotary machines tend to be more stable, quieter and less likely to fail.
The Boiler
The boiler is the element that heats water to the ideal temperature for extraction. The resulting steam reaches the portafilter containing the ground espresso and is then funneled down into the cup. The steam creates enough pressure to push the coffee grounds through. This results in a layer crema on top. This is one of the main characteristics of a great espresso.
There are three types of espresso machines, each having distinct pumps and the temperature of the brew. There are various ways in which the brew could be controlled, as well as the size of the cup that the maker can create.
The first espresso machines were steam-types. They had one boiler to make both brew and steam, but the pressure they could generate was low - only two bars of atmospheric pressure at most. The coffee tasted bitter and burned. The modern espresso machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most popular espresso machine is a semiautomatic one with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine, you grind the beans and tamp them by hand. However, the pump provides regulated water flow and pressure. This is a perfect compromise between human control and mechanised accuracy.
The Filter
Espresso machines typically have a filter that separates the coffee grounds from the hot water. The website filter is also an important component of the temperature control system, since it helps prevent the machine from overheating.
It also improves flavor, as it allows for a more prolonged bloom phase. This allows the beans to release their nuances and gives the chance for better extraction.
However, it is important to keep in mind that even a top filter can make a terrible cup of coffee, because the quality of the beans and extraction is still vital.
It's in this area that the magic occurs. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you place the portafilter - the thingy that you use to put the grounds of coffee into when making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. This then pushes the hot water through the grounds at high pressure. These types of machines tend to be cheaper and easier to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have become more popular. They utilize an air compressor to push hot water into the grounds and are more portable than electric steam-driven machines.