How To Explain Machine Espresso To Your Grandparents
How To Explain Machine Espresso To Your Grandparents
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How Does Machine Espresso Work?
The machine espresso uses precise pressure and filtering technology that is amazing to create the coffee you enjoy. How exactly does it work?
Espresso is made by pushing hot water under high pressure through finely-ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.
The Head of the Group
The group head is the portafilter is inserted when you are making espresso. It disperses water into the portafilter, and then regulates the pressure of extraction. There are numerous kinds of group heads each with their own advantages and disadvantages. Some are designed to provide stability in temperature, while others are specifically designed to handle pre-infusion. Some are designed to control the lever. Some include a combination such as the E61. This is a favorite among baristas due to the fact that it has multiple advantages in a single package.
As you can see in the photo above The group head features numerous notches that you can put your portafilter, then twist it manually to secure it. A gasket of rubber is situated in the notches to create a seal while you insert your portafilter. The notches allow for precise placement of the portafilter. This is crucial to ensure an even extraction.
The group head does not just allow you to insert your portafilter easily however, it also keeps an even temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is constant to extract the coffee. It is important to realize that even a slight differences can make the distinction between a good and a excellent espresso.
The Pump
Unlike manual piston machines, which rely on a lever to pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure needed for espresso extraction. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be less expensive than piston-driven machines, and they tend to last longer, however both types of machines could get damaged through overuse and lack of cleaning. They also make mechanically complex, which can result in costly prices for even the most basic models.
Certain espresso machines can eliminate the pump entirely and utilize steam pressure to make espresso. The drawback is that the same boiler that produces steam also increases the temperature of the water to the point of boiling, which can lead to over-extraction. Additionally these machines typically have 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 using a rotating disc to create the pressure, and the rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, but rotary machines are more stable, quieter and less likely to break down.
The Boiler
The boiler is the element that heats the water to the ideal temperature for extraction. The steam that is produced reaches the portafilter, which is a container for espresso grounds. It is then poured into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a layer crema that is then poured over. This is a hallmark of a good espresso.
There are three distinct types of espresso machines, each having distinct pumps and the temperature of the brew. There are also different ways in which the brew can be controlled, as well as the size of the cup that the machine can make.
The first espresso machines were steam-type. They employed one boiler to make both steam and brew, but the pressure they could create was minimal - two bars of atmospheric pressure at the most. The coffee tasted bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most well-known espresso machine is a semiautomatic that has an electric pump. These are the images people have when they think of an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself while the pump controls the flow of water and pressure. This is an excellent compromise between human touch and mechanized consistency.
The Filter
Typically, espresso machines employ filters to separate the grounds of coffee when they pass through the hot water. The filter is also an essential component of the machine's temp control, as it prevents overheating.
It also helps with flavor, as a filter can allow for a longer bloom time. This allows the beans to let their nuances out, and also allows for better extraction.
It is important to keep in mind that even the most efficient filter can produce a bad cup of coffee. The quality of the beans and the extraction process are still crucial.
It's in this area that the magic happens. This is the reason why espresso tastes so good. The grouphead, sometimes called the brewhead, is where the portafilter (the thingy you espresso machine coffee put the coffee ground into) is located when you're making espresso.
In a steam-driven espresso machine hot water is heated in an airtight container to create steam. This then pushes the hot water through the grounds at a high pressure. These kinds of machines are generally cheaper and easier to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent times, espresso machines powered by a compressed air pump have become increasingly popular. They use an air compressor to force hot water through grounds, and are far more portable than electric steam-driven machines.