9 . What 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 perfect cup of coffee. How does it work exactly?

To make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However it is the pressure that makes the main difference.

The Head of the Group

As the name suggests, the group head is where you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter and controlling the pressure that results from the extraction. There are a variety of types of group heads, each with their own advantages and disadvantages. Some are specifically designed for the stability of temperature while some are built to handle pre-infusion. Others are made to control the lever. Some have a combination, such as the E61. This is a very popular choice for baristas as it provides a variety of advantages in one package.

As you can see in the above image the group head is made up of many notches in which you can place your portafilter and twist it by hand to secure it. A gasket of rubber is situated within the notches to create a seal when you insert your portafilter. The notches on the head permit a precise position of the portafilter which is vital to ensure a consistent extraction.

Aside from allowing you to easily place your portafilter in, the group head is responsible to maintain an even temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is at the right level to extract the coffee. It is important to remember that even a slight difference can make the difference between a great and a excellent espresso.

The Pump

Motorized pumps in espresso machines rotary provide nine atmospheric bar pressure required for espresso extraction. This differs from manually operated piston machines that employ levers. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee in the group head.

Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines may degrade because of frequent use and insufficient cleaning. Pumps are also more complex mechanically, which can increase the price of even the most basic models.

Some espresso machines can eliminate the pump entirely and make use of steam pressure to make espresso. The disadvantage of this is that the same boiler that produces steam also raises the temperature of the water to the point of boiling, which can lead to over-extraction. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many italian espresso machine machines make use of a rotary or vibration pump. A vibration model employs a rotating disk to generate pressure, while a circular model pushes hot liquid through the best ground coffee for espresso machine at a rapid speed. Both models can make a great best espresso maker, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is the element that heats the water to the ideal temperature for extraction. The resulting steam reaches the portafilter containing ground espresso beans and is then pumped into the cup. During this process the steam creates enough pressure to push the grounds of coffee through. This creates a layer crema that is then poured over. This is a hallmark of a good espresso.

There are three types of espresso makers. They differ in the type of pump they employ and the degree of heat that the espresso is. There are also different ways that the brew can be controlled and the size of the cup that the machine can produce.

The first espresso machines were steam type. They used only one boiler to make steam and brew, however, the pressure they could produce was very low - just two bars of atmospheric pressure at most. This led to the coffee tasting burnt and bitter. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.

The most well-known discount espresso machines maker is a semi-automatic machine with an electric pump. These are the things people think of when they think of an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself however the pump controls the flow of water and pressure. This is a perfect combination of human control and mechanized consistency.

The Filter

Espresso machines typically have a filter that separates the grounds of the coffee espresso machines from hot water. The filter is also a vital component of the machine's temp control, since it helps to prevent overheating.

A filter also helps with flavor as it allows for a longer flowering phase. This allows the beans to let their nuances out, and improves extraction.

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

This is where the magic happens, it's what makes an espresso really taste good. The grouphead, sometimes referred to as the brew head, is the place where the portafilter (the thingy you put the ground coffee in) sits when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated in an airtight container to create steam. The steam then moves hot water through the coffee grounds under high pressure. These kinds of machines tend to be less expensive and easier to maintain than pumps-driven models. However, they are limited in their ability to provide the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.

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