5 Laws To Help The Machine Espresso Industry
5 Laws To Help The Machine Espresso Industry
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How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to make the perfect cup of coffee. How exactly does it work?
In order 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 Head of the Group
The group head is the portafilter that you put in when making espresso. It is responsible for dispersing water into the portafilter and then controlling the pressure of the extraction. There are many different types of group heads, each with its own advantages and disadvantages. Some focus on temperature stability, whereas others on pre-infusion capabilities, while others are designed to control the lever. Some come with a combination of both, such as the E61. This is a favorite among baristas as it provides a variety of advantages in a single package.
As you can see in the image above the head of the group is fitted with a variety of notches. The portafilter is placed into these notches and turn the head around 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 precise placement of your portafilter. This is crucial to ensure a consistent extraction.
The group head not only lets you to place your portafilter easily, but it also maintains the temperature at a constant level. This is done by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is at the right level for extraction. This is important, as even a small difference in temperature can make the difference between good and great espresso.
The Pump
Unlike manual piston machines, which use a lever to pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure needed to extract espresso. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.
Pumps are generally less expensive than piston-driven machines, and tend to last longer, although both types of machines could become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, and can add to the price of even the simplest models.
Certain espresso machines utilize steam pressure instead of a pump to make espresso. This can lead to over-extraction as the boiler that makes steam also heats the water to boil. These machines also have to constantly rebuild their pressure in between cups. This takes energy and time.
Many espresso machines use the rotary or vibration pump. A vibration model best home espresso machine employs the vibrating disk to create pressure, whereas a Rotary model pushes hot coffee 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 an optimal temperature for extraction. The steam that is created gets to the portafilter which is the container that holds the espresso coffee grounds. It is then funneled into the cup. During this process the steam creates enough pressure to push the grounds of the coffee through. This produces a layer of crema that is then poured over. This is the hallmark of a good espresso.
There are three types of espresso makers. They differ in the kind of pump they use and how hot the brew is. There are different ways to control the amount of brew, as well as the size of the cup that can be made by the machine.
The first espresso machines were steam types. They used one boiler to create both brew and steam, however, the pressure they could create was minimal - two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most well-known espresso maker is a semi-automatic one that has an electric pump. These are what people imagine when they think of an espresso maker. With a semi-automatic espresso machine, you grind the beans and tamp them by hand. However, the pump regulates the flow of water and pressure. This is a perfect solution that combines human control with mechanised accuracy.
The Filter
Espresso machines usually use filters that separate the coffee grounds from the hot water. The filter is also a crucial part of the temperature control system because it stops the machine from overheating.
It also helps with flavor, since a filter allows for a more prolonged bloom time. This allows beans to release their nuances and gives an opportunity for a better extraction.
It is important to keep in mind that even the most efficient filter could result in a poor cup of coffee. The quality of the beans, and the extraction process, are still crucial.
It's here that the magic takes place. This is what makes espresso taste so delicious. The grouphead, sometimes referred to as the brew head, is where the portafilter (the thingy you put the coffee ground into) is placed when making espresso.
Steam-driven espresso machines make use of hot water that is heated in an airtight vessel to create steam. The steam then pushes hot water into the grounds of coffee at high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are not as efficient in their ability to provide the perfect conditions for brewing, since they operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have been gaining popularity. They make use of an air compressor to force hot water into the ground and are much more mobile than electric steam-driven espresso machines.