Nine Things That Your Parent Taught You About Machine Espresso > 자유게시판

How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and incredible filter technology to produce the coffee we love. How does it work exactly?

Espresso is created by forcing hot water at high 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

The group head is the portafilter you insert when brewing espresso. It distributes water into the portafilter and regulates the pressure of extraction. There are many different kinds of group head each with its own advantages and disadvantages. Some are specifically designed for temperature stability while others are built to handle pre-infusion. Some are designed to control the lever. There are also some that come with a range of features, like the E61, which is considered to be the most popular among baristas for its ability to provide multiple benefits in one package.

As you can see from the picture above, the group head is fitted with a variety of notches. It is possible to place your portafilter inside these notches, and then twist the head to lock it. There is also a rubber gasket that resides inside the notches, which helps create an airtight seal after inserting your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is crucial for an even extraction.

The group head does not just allow you to place your portafilter easily but also maintains 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. It is crucial to keep in mind that even a small difference can make the difference between a great and a great espresso.

The Pump

Contrary to manual piston machines that use a lever to pressurize water, Rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure needed for espresso extraction. The pressure is created by removing tap water from a reservoir, and pumping it through a heat exchanger prior being pumped through the ground coffee in the group head.

Pumps tend to be less expensive than piston-driven machines, and tend to last longer, but both types of machines can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, which can increase the cost of even the simpler models.

Some espresso machines employ steam pressure instead of a pump to make espresso. This can result in over-extraction because the boiler that produces steam also heats the water until it comes to a boil. The machines must also constantly rebuild their pressure in between cups. This requires energy and time.

Many espresso machines utilize a vibration or rotary pump, with a vibration model using a rotating disc to generate the pressure, and a rotary model pushing hot water through the grounds under high speed. Both machines can make excellent espresso coffee machine with milk frother however rotary machines tend to be more stable, quieter and less likely to fail.

The Boiler

The boiler is the part that heats water to an ideal temperature to extract. The resultant steam then reaches the portafilter containing the ground espresso and is then pumped down into the cup. During this process, the steam creates pressure that pushes through the coffee grounds. This results in a whipped-up the top of the espresso. This is a hallmark of a good espresso.

There are three types of espresso makers, and they differ in the type of pump they use and the degree of heat that the coffee is. There are a variety of 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 had a single boiler to make steam and brew, however, the pressure they could produce was very low - just two bars of atmospheric pressure maximum. This led to the coffee tasting bitter and burnt. This is why the Milanese makers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most common professional espresso maker machine is a semiautomatic that has an electric pump. When people think of espresso machines, they picture these machines. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized quality.

The Filter

Espresso machines typically use filters that separate the grounds of the coffee from the hot water. The filter is also an essential component of the temperature control system, because it stops the machine from overheating.

A filter can also help with flavor because it allows for a longer flowering phase. This lets the beans release their nuances, and allows for better extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans, as well as the extraction, are still crucial.

This is where the magic happens, it's the thing that makes espresso taste great. The grouphead, often called the brew head, is where the portafilter (the device you put the coffee grounds into) is placed when you're making espresso.

In a steam-driven espresso machine hot water is heated in an airtight tank to produce steam, which is then pushed through the grounds with high pressure. These machines are cheaper and easier to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing as they only 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 become more popular. They utilize an air compressor to force hot water through the ground, and are more mobile than steam-driven electric espresso machines.