14 Cartoons About Machine Espresso That Will Brighten Your Day
From Shiapedia
How Does Machine Espresso Work?
The machine espresso utilizes precision pressure, and a filtering system that is awe-inspiring to create the coffee you love. How exactly does it work?
In order to make espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the key difference is in the pressure.
The Group Head
The name implies the group head is the place you put your portafilter in when making espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure that results from the extraction. There are numerous kinds of group heads each with distinct advantages and disadvantages. Some are designed to provide temperature stability while others are specifically designed to handle pre-infusion. Some are designed to control the lever. Some are a combination, such as the E61. This is a favorite among baristas because it offers multiple benefits in one package.
As you can see in the above photo the group head is equipped with several notches. It is possible to place your portafilter in these notches and then twist the head to lock it. There is also a gasket made of rubber in the notches and helps create the seal when you insert your portafilter into the machine. The notches on the head allow for an exact location of the portafilter which is necessary for an efficient extraction.
The group head not only allows the portafilter to be inserted easily but also maintains an even temperature. It does this by circulating hot water through the brew pan and around the portafilter to ensure that it is always at the correct temperature for extraction. This is vital, because even a small difference in temperature can make the difference between good and great espresso.
The Pump
In contrast to piston machines that are manually operated, that use a lever to pressurize water, rotating retro espresso maker machines rely upon motorized pumps to supply the nine atmospheric bars of pressure necessary to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee.
Pumps tend to be cheaper than piston-driven machines and tend to last longer, however both types of machines could be damaged by excessive use and inadequate cleaning. They also make mechanically complex, which can result in a high price tag on even the simplest models.
Certain espresso and filter coffee machine (read full article) machines remove the pump entirely and make use of steam pressure to make espresso. This can cause over-extraction because the boiler that makes steam also heats the water to boil. They also have to continuously rebuild their pressure between cups. This requires energy and time.
Many espresso machines use either a vibration or rotary pump. A vibration model uses a vibrating disk to generate pressure, whereas the rotary model pushes hot water through the ground at a fast speed. Both types of machines are capable of producing excellent espresso, but rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is what will heat the water to the ideal temperature to extract. The steam that is produced reaches the portafilter, which contains the ground espresso coffee and is then funneled down into the cup. The steam creates enough pressure to push the grounds of coffee through. This results in a whipped-up top of the espresso. This is one of the hallmarks of a good espresso.
There are three types of espresso makers, and they differ in the type of pump they employ and how hot the coffee is. There are many ways to control the brew and the size of the cup that can be made by the machine.
The first espresso machines were steam-type. The first espresso machine black friday machines were steam types. This resulted in the coffee tasting burnt and bitter. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most popular espresso maker is a semi-automatic one with an electric pump. These are what people imagine when they think of an espresso maker. If you have a semi-automatic machine you grind the beans and tamp them by hand. However, the pump controls the flow of water and pressure. This is an excellent combination of human control and mechanized reliability.
The Filter
Typically, espresso machines use a filter to separate out the coffee grounds as they pass through the hot water. The filter is also a vital component of the machine's temp control, since it stops overheating.
A filter also helps with flavor, as it permits an extended flowering time. This helps the beans release their nuances and gives an opportunity for a better extraction.
However it is crucial to keep in mind that even a high-quality filter can make a terrible cup of coffee as the quality of the beans and extraction are vital.
It's in this area that the magic takes place. This is what makes espresso taste so delicious. The grouphead, often called the brewhead, is where the portafilter (the container you place the coffee grounds into) is located when you're making espresso.
In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds at high pressure. These types of machines are generally less expensive and simpler 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 been gaining popularity. They utilize an air compressor to force hot water through the grounds and are much more portable than electric steam-driven machines.
