10 Things That Your Family Taught You About Machine Espresso > 자유게시판

How Does Machine Espresso Work?

Machine espresso machine small utilizes precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it that makes it work?

To make an espresso, hot water is forced under high end espresso machine pressure through finely ground coffee. The process is similar to making drip coffee, but the major difference is in the pressure.

The Head of the Group

As the name suggests, the group head is the place you put your portafilter in when brewing espresso. It disperses water in the portafilter and controls the pressure of the extraction. There are a variety of types of group head each with its particular advantages and drawbacks. Some focus on temperature stability, while others on pre-infusion features, and others are designed to control the lever. Some come with a combination of both, such as the E61. This is a preferred choice for baristas since it provides multiple advantages in one package.

As you can see in the picture above the group head is fitted with several notches. You can place your portafilter inside these notches, and then twist the head to lock it. There is also a gasket of rubber which is located inside the notches and helps create the seal when you insert your portafilter into the machine. The notches on the head permit a precise location of the portafilter which is essential for a consistent extraction.

The group head does not just allow you to place your portafilter easily however, it also keeps the temperature at a constant level. This is accomplished by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is at the right level for extraction. It is important to note that even a small variation can mean the difference between a decent and a excellent espresso.

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 rely on a lever. The pressure builds up by removing 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 models, and they tend to last longer, although both types of machines could be damaged by excessive use and inadequate cleaning. Pumps are also more complex mechanically, and can add to the cost of even simple models.

Some espresso machines employ steam pressure instead of a pump for brewing espresso. This can cause over-extraction because the boiler that makes steam also causes the water to boil. In addition these machines typically have to restore their pressure between cups, which takes time and energy.

Many espresso machines utilize an rotary or vibrating pump, which has a vibration model using a vibrating disc to create the pressure and a rotary model pushing hot water through the grounds under high speed. Both models can produce an excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element which heats the water to the ideal temperature for extraction. The steam that is produced reaches the portafilter which holds the ground espresso coffee, and is then funneled down into the cup. In this process, the steam causes pressure to push through the grounds of the coffee. This results in a layer crema that is then poured over. This is a sign of a great espresso.

There are three kinds of espresso makers, which differ in the type of pump they employ and the degree of heat that the espresso is. There are different ways to control the strength of the brew and the size of cup that can be produced by the machine.

The earliest espresso machines were steam-based. They had one boiler to make both brew and steam, however, the pressure they could generate was low - only two bars of atmospheric pressure at the most. This resulted in the coffee tasting burnt and bitter. This is why the Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most well-known espresso maker is a semi-automatic one with an electric pump. When people think of espresso machines, they envision these machines. With a semi-automatic espresso machine, you must grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is a fantastic combination of human control and mechanised consistency.

The Filter

Typically, espresso machines employ filters that separate 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 a longer flowering period. This allows beans to release their flavor and gives an opportunity to improve extraction.

However, it is important to keep in mind that even a good filter could result in a bad cup of coffee, since the quality of the beans and extraction are essential.

This is where the magic happens. It's what makes an espresso really taste good. The grouphead, also referred to as the brew head, is where the portafilter (the thingy you put the ground coffee and espresso maker in) is placed when making espresso coffee machine home.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to create steam. The steam then pushes hot water through the coffee grounds under high pressure. These kinds of machines are typically cheaper and easier to maintain than pump-driven models. However, they are not as efficient in their ability to produce the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, compressed-air-pump-driven espresso machines have become more popular. They utilize an air compressor to force hot water through the grounds and are significantly more portable than electric steam-driven machines.