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How Does Machine Espresso Work?

The machine espresso utilizes precision pressure, and a filter technology that is mind-blowing to create the coffee you enjoy. What exactly does it work?

In order to make espresso coffee Machines for sale, 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 main difference.

The Group Head

The group head is the portafilter that you insert when brewing home espresso machine. It distributes water into the portafilter, and regulates the pressure during the extraction. There are many different kinds of group head each with its own advantages and drawbacks. Some are designed to provide temperature stability while others are specifically designed to handle pre-infusion. Some are designed to control the lever. Some have a combination, such as the E61. This is a preferred choice for baristas since it provides multiple benefits in one package.

As you can see from the picture above the head of the group is fitted with a variety of notches. You place your portafilter in these notches, then twist the head to secure it. A gasket made of rubber is positioned inside the notches to help create a seal as you insert your portafilter. The notches on the head permit a precise location of the portafilter which is vital for an even extraction.

Aside from allowing you to effortlessly insert your portafilter the group head is also responsible to maintain an even temperature. This is achieved by cycling hot water around the portafilter, and through the brew-basket to ensure the temperature is always right for extraction. This is important because even a few degrees can mean the difference between good and excellent espresso.

The Pump

The motorized pumps used in rotary espresso machines supply the nine atmospheric bars of pressure required for espresso extraction. This differs from manual piston machines that use a lever. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.

Pumps are typically less expensive than piston-driven machines, and tend to last longer, but both types of machines could get damaged through overuse and lack of cleaning. Pumps are also more complex mechanically, which could increase prices of even simple models.

Some espresso machines use steam pressure instead of a pump for brewing espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of the water to the point of boiling which can cause excessive extraction. In addition the machines often have to rebuild their pressure between cups, which takes time and energy.

A majority of espresso machines use the rotary or vibration pump, with a vibration model that uses a vibrating disc to create pressure and rotating models that push hot water through the grounds under high speed. Both machines can make great espresso, however rotary machines are more stable, quieter and less likely to break.

The Boiler

The boiler is used to heat the water to the perfect temperature for extraction. The steam that is produced gets to the portafilter which contains the espresso coffee grounds. It is then poured into the cup. In this process, the steam creates pressure to push through the coffee grounds. This results in a whipped-up top of the espresso. This is the hallmark of a great espresso.

There are three different types of espresso machines, each with different types of pumps and brew temperature. There are also different ways that the brew can be controlled as well as the dimensions of the cup the machine can produce.

The first espresso machines were steam-types. The first espresso machines were steam types. The coffee tasted bitter and burned. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic device that has an electric pump. These are the images people have when they think of an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself however the pump controls the water flow and pressure. This is a great compromise between the human touch and mechanized quality espresso machine.

The Filter

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

A filter also improves flavor since it allows for an extended flowering time. This allows the beans to release their nuances, and also allows for better extraction.

It is important to keep in mind that even the most efficient filter could result in a poor cup of coffee. The quality of the beans and the extraction, are still very important.

It's here that the magic takes place. This is what makes espresso taste so good. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy used to place the coffee grounds into, when making espresso.

In a steam-driven espresso machine hot water is heated in an airtight tank to create steam, which is then pushed through the grounds at a high pressure. These machines are cheaper and easier to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing since 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 use an air compressor to push hot water across the ground and are more mobile than steam-driven electric espresso machines.