A Vibrant Rant About Machine Espresso > 자유게시판

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How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and amazing filter technology to make the perfect cup of coffee. What exactly does it work?

Espresso is made by forcing hot water under pressure through finely-ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.

The Group Head

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter before controlling the pressure of the extraction. There are various kinds of group heads, each with their own advantages and disadvantages. Some focus on temperature stability, some on pre-infusion capabilities, while others are designed to control the lever. There are even some that have a combination of features, like the E61 one, which is the standard choice for many baristas for its ability to provide multiple benefits in one package.

As you can see in the above image The group head features several notches where you put your portafilter, then twist it manually to secure it. A gasket made of rubber is positioned within the notches to create a seal when you insert your portafilter. The notches permit an exact placement of the portafilter. This is essential for an even extraction.

In addition to allowing you easily place your portafilter in, the group head is also responsible to maintain an even temperature. 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. This is important, as just a few degrees could mean the difference between good and excellent espresso.

The Pump

In contrast to piston machines that are manually operated, which use a lever to pressurize water, rotary mini espresso maker machines rely on motorized pumps to provide the nine atmospheric bars of pressure that are required to extract espresso. This pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior it is shot through the ground coffee inside the group head.

Pumps are generally less expensive and last longer than piston-driven machines. However, both types of machines can deteriorate due to overuse and poor cleaning. They also create mechanical complexity and can lead to a high price tag on even the simplest models.

Certain espresso machines remove the pump entirely and use steam pressure to brew espresso. This can lead to over-extraction as the boiler that produces steam also heats the water to boil. These machines also have to continually rebuild their pressure between cups. This requires energy and time.

Many espresso machines utilize a vibration or rotary pump, with a vibration model that uses a vibrating disc to create the pressure, and the rotary model pushing hot water through the grounds at high speed. Both models are capable of producing excellent espresso, but rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the one that will heat the water to a temperature that is ideal for extraction. The steam that is produced is then directed to the portafilter, which is the container that holds the espresso maker for home coffee grounds. The steam is then channeled into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This results in a crema on the top of the espresso. This is a sign of a great espresso.

There are three types of espresso machines, each with different types of pumps and the temperature of the brew. There are different ways to control the brew and the size of the cup that can be made by the machine.

The earliest espresso machines were steam type. The earliest espresso machines were steam types. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

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

The Filter

Typically, espresso makers 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 temperature control, as it prevents overheating.

A filter can also help with flavor, as it permits an extended flowering time. This helps the beans to let their nuances out and provides an opportunity for better extraction.

However, it is important to remember that even a top filter can make a terrible cup of coffee, since the quality of the beans and extraction is crucial.

This is where the magic happens, it's what makes buy espresso machine taste good. The grouphead, sometimes referred to as the brewhead, is where the portafilter (the thingy you put the ground coffee in) is located when you're making espresso.

Steam-driven espresso machines use hot water that is heated inside an airtight container to make steam. The steam then moves hot water through the grounds of the coffee under pressure. They are less expensive and easier to maintain than pumps-driven models. They are however limited in their ability for creating the ideal conditions for brewing, as they operate with 1-1.5 bar of pressure. The perfect shot requires 9 bar espresso machine-10 bars.

In recent years, compressed air pump-driven espresso machines have become more popular. They use an air-compressor to push hot water through the ground. They are also more mobile than electric steam-driven espresso machines.