• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

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?

Espresso is produced by pushing hot water under pressure through finely ground coffee. The process is similar to that of making drip coffee machine espresso. However, the pressure is the primary difference.

The Group Head

The group head is the portafilter you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are numerous kinds of group heads each with distinct advantages and drawbacks. Some are designed to provide the stability of temperature while some are specifically designed to handle pre-infusion. Others are built to control the lever. Some come with a combination of both, like the E61. This is a preferred choice for baristas due to the fact that it has multiple benefits in a single package.

As you can see from the above photo the head of the group is equipped with several notches. You place your portafilter in these notches and then turn the head around to secure it. There is also a gasket of rubber in the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is essential for a consistent extraction.

Aside from allowing you to easily place your portafilter in, the group head is also responsible to maintain an even temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right to extract the coffee. This is important, as just a few degrees could be the difference between a excellent and great espresso coffee makers.

The Pump

Motorized pumps in espresso machines that rotate provide the nine atmospheric bar pressure that is required to extract espresso. This is different from manual piston machines that use a lever. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps are typically less expensive and last longer than piston-driven machines. However, both types of machines can deteriorate due to overuse and poor cleaning. Pumps are also more complicated mechanically, which can raise the cost of even simple models.

Some espresso machines use steam pressure instead of a pump in order to brew espresso. This can result in over-extraction because the boiler that produces steam also heats the water until it comes to a boil. Additionally the machines often have to restore their pressure between cups, which requires time and energy.

A majority of espresso machines utilize the rotary or vibration pump. A vibration model makes use of an oscillating disk to create pressure, while a Rotary model pushes hot coffee through the ground at high speed. Both machines can produce excellent espresso however rotary machines tend to be more quiet, durable and less likely to fail.

The Boiler

The boiler is the element that heats water to the ideal temperature for extraction. The steam that is produced reaches the portafilter that contains ground espresso beans and is then pumped into the cup. The steam is able to create enough pressure to push the coffee grounds through. This creates a crema on the top of the espresso. This is one of the hallmarks of a great espresso.

There are three different types of espresso machines, each with different types of pumps and brew temperature. There are also different ways that the brew can be controlled as well as the size of the cup that the machine is capable of making.

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

The most well-known espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans by yourself, but the pump regulates the flow of water and pressure. This is a fantastic combination of human control and mechanized reliability.

The Filter

Espresso machines usually have filters that separate the grounds of the coffee from the hot water. The filter is also a crucial element of the temperature control system since it helps prevent the machine from overheating.

A filter also helps with flavor, as it permits an extended flowering time. This lets the beans let their nuances out, and allows for a better extraction.

It is important to remember that even the best filter can make a bad cup of coffee. The quality of the beans and the extraction process, remain vital.

This is where the magic happens, it's the thing that makes an espresso really taste great. The grouphead, also referred to as the brew head, is the place where the portafilter (the container you place the ground coffee into) is located when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight tank to create steam. This is then pushed through the grounds at a high pressure. These types of machines are usually cheaper and easier to maintain than pump-driven models. However, they are not as efficient in their ability to produce the ideal brewing conditions, because they operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.

In recent years, compressed-air-pump-driven espresso machines have been gaining popularity. They use an air compressor to force hot water through the grounds, and are far more portable than electric espresso maker steam-driven machines.