A Provocative Rant About Machine Espresso > 자유게시판

How Does Machine Espresso Work?

Machine espresso uses precision pressure and incredible filter technology to produce the delicious coffee we enjoy. But how exactly does it work?

In order to make espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee, but the key 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 disperses the water into the portafilter, and controls the pressure of the extraction. There are a variety of types of group heads each with its particular advantages and disadvantages. Some are designed to provide stability in temperature, while others are built to handle pre-infusion. Others are built bean to cup espresso machines control the lever. Some have a combination, such as the E61. This is a popular choice among baristas as it provides a variety of benefits in a single package.

As you can see from the photo above the group head is equipped with several notches. It is possible to place your portafilter in these notches and then twist the head to lock it. There is also a rubber gasket in the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head allow for an exact positioning of the portafilter which is vital to ensure an even extraction.

The group head not only allows you to put in your portafilter easily but also maintains the same temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is always at the right level to extract the coffee. It is important to note that even a small variation can mean the difference between a great and a excellent espresso.

The Pump

In contrast to manual piston machines which use a lever to pressurize water, rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure needed for espresso extraction. The pressure is created by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally less expensive and last for longer than piston-driven machines. However, both kinds of machines may degrade due to excessive use and insufficient cleaning. They also increase the complexity of mechanical systems that can lead to an expensive price for even the simplest models.

Some espresso machines can eliminate the pump entirely and make use of steam pressure to make espresso. The downside is that the same boiler that produces steam also raises the temperature of the water to boiling and can result in over-extraction. In addition, these machines frequently have to restore their pressure between cups, which requires time and energy.

Many espresso machines employ the rotary or vibration pump, with a vibration model using a rotating disc that generates the pressure and rotating models that push hot water through the grounds under high speed. Both machines can make excellent espresso however rotary machines tend to be more stable, quieter and less likely to fail.

The Boiler

The boiler is the component that heats water to the optimal temperature for extraction. The steam that is produced reaches the portafilter which holds the ground espresso and gets funnelled down into the cup. During this process the steam causes enough pressure to push the grounds of the coffee through. This results in a whipped-up the top of the espresso. This is one of the main characteristics of a good espresso.

There are three types of espresso makers, and they differ in the type of pump they employ and how hot the coffee is. There are many ways to control the amount of brew, as well as the size of cup that can be made by the machine.

The first espresso machines were steam-type. They used only one boiler to make both steam and brew however the pressure they were able to generate was low - only two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. The modern espresso machine was created by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most commonly used espresso maker is a semi-automatic one that has an electric pump. This is what people envision when they think of an espresso maker. Semi-automatic machines require you to grind and tamp the beans yourself, but the pump regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

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

It also enhances flavor, as a filter can allow for a longer bloom time. This allows the beans to release their flavors, and also allows for better extraction.

It is important to keep in mind 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, sometimes called the brew head, is where the portafilter (the device you put the ground coffee into) is located when you're making espresso coffee machine with milk frother.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to make steam. The steam then pushes hot water through the grounds of the coffee under pressure. These kinds of machines are typically less expensive and simpler to maintain than pump-driven models. They are however limited in their ability to create the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

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