9 Things Your Parents Taught You About Machine Espresso > 자유게시판

How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to make the delicious coffee we enjoy. How exactly does it work?

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 major difference.

The Head of the Group

The group head is the portafilter that you put in when making espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure of the extraction. There are several different types of group head each with its particular advantages and disadvantages. Some are specifically designed for stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some come with a combination of both, such as the E61. This is a favorite among baristas due to the fact that it has multiple advantages in a single package.

As you can see in the above photo the group head comes with numerous notches that you can place your portafilter and twist it by hand to secure it. A gasket of rubber is situated within the notches to make a seal when you insert your portafilter. The notches allow for an exact placement of the portafilter. This is vital for an efficient extraction.

The group head not only allows the portafilter to be inserted easily but also maintains an even temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is constant for extraction. This is important, as even a few degrees can mean the difference between excellent and great espresso.

The Pump

The motorized pumps used in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This is different from manual piston machines that rely on levers. This pressure is built up by pumping water through a heat-exchanger and then through the ground coffee.

Pumps tend to be less expensive and last longer than piston-driven machines. However, both types of machines are susceptible to degrading due to excessive use and poor cleaning. Pumps are also more complicated mechanically, which can increase prices of even simple models.

Certain espresso machines can eliminate the pump entirely and employ steam pressure to create espresso. This can cause over-extraction because the boiler that makes steam also heats the water until it comes to a boil. The machines must also continuously rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines use a vibration or rotary pump, with a vibration model using a vibrating disc to create pressure, and the rotary model pushing hot water through the grounds under high speed. Both machines can make great espresso, but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is the component which heats the water to the optimal temperature for extraction. The steam created gets to the portafilter which holds the espresso grounds. The steam is then channeled into the cup. During this process, the steam causes pressure to push through the grounds of the coffee. This results in a crema on top of the espresso. This is one of the main characteristics of a good espresso.

There are three different types of espresso machines, each having different types of pumps and brew temperature. There are different ways that the brew can be controlled and the size of the cup the machine can make.

The earliest espresso machines were steam type. The first espresso machines were steam-type machines. This led to the coffee tasting bitter and burnt. The modern professional espresso machine machine was created by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semiautomatic machine with an electric pump. When people think of espresso machines, they picture these machines. With a semi-automatic machine, you have to grind the beans and tamp them yourself but the pump regulates the flow of water and pressure. This is a great compromise between human control and mechanized accuracy.

The Filter

Typically, espresso machines have filters to separate the coffee grounds as they pass through the hot water. The filter is also a vital component of the machine's temperature control, since it helps to prevent overheating.

It also enhances flavor as a filter lets you enjoy a longer bloom phase. This allows the beans to let their nuances out and provides an opportunity to improve extraction.

However, it is important to remember that even a great filter can result in a poor cup of coffee, as the quality of the beans and extraction is essential.

It's here that the magic happens. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you put the portafilter, which is the thingy that you put the grounds of your coffee into when making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds under high pressure. These machines are less expensive and easier to maintain than pumps-driven models. However, they are not as efficient in their capacity to create the perfect brewing conditions as they only operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, mini espresso maker machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to force hot water through the ground, and are more mobile than steam-driven electric espresso machines.