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How Does Machine Espresso Work?

The machine espresso uses precision pressure, and a filtering technology that is amazing to make the coffee you love. How exactly does it work?

To make buy espresso makers 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

As the name suggests, the group head is the place you place your portafilter while making espresso. It disperses the water into the portafilter, and then regulates the pressure of the extraction. There are various kinds of group head each with its own advantages and disadvantages. Some focus on temperature stability, others on pre-infusion features, and others are designed to control the lever. Some come with a range of features, like the E61 that is the classic choice among many baristas because of its ability to offer multiple perks in a single package.

As you can see in the above image the group head comes with several notches where you place your portafilter before twisting it manually to secure it. A gasket made of rubber is placed within the notches to make a seal when you insert your portafilter. The notches permit an exact placement of the portafilter. This is vital for an even extraction.

The group head not only allows the portafilter to be inserted easily, but it also maintains an even temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket to ensure that the temperature is constant to extract the coffee. This is important, as even a small difference in temperature can be the difference between a good and great home espresso machine.

The Pump

Motorized pumps in rotary espresso machines provide the nine atmospheric bars of pressure required to extract espresso coffee machine home. This is different from manual piston machines that use levers. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior it is shot through the ground coffee inside the group head.

Pumps tend to be cheaper than piston-driven models, and they tend to last longer. However, both types of machine can degrade with overuse and insufficient cleaning. They also create mechanical complexity which can result in an expensive price for even the most basic models.

Some espresso machines remove the pump completely and employ steam pressure to create best budget espresso machine. This could lead to over-extraction since the boiler that produces steam also heats the water to boil. The machines must also continually rebuild their pressure between cups. This requires energy and time.

A large majority of espresso machines employ either a vibration or rotary pump. A vibration model utilizes the vibrating disk to create pressure, while a rotary model pushes hot water through the ground at a high speed. Both machines can produce excellent espresso however rotary machines tend to be more quiet, durable and less likely to break down.

The Boiler

The boiler is the element which heats the water to the optimal temperature to extract. The resultant steam then reaches the portafilter that contains the ground espresso coffee, and is then pumped into the cup. During this process the steam is able to create enough pressure to push the grounds of coffee through. This creates a layer crema that is then poured over. This is the hallmark of a great espresso.

There are three distinct types of espresso machines, each with different pumps and the temperature of the brew. There are different ways that the brew can be controlled and the size of the cup the machine is capable of making.

The earliest espresso machines were steam type. The earliest espresso machines were steam types. The coffee tasted bitter and burned. The modern espresso machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso machine is a semiautomatic with an electric pump. These are the images people have when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans by yourself while the pump controls the water flow and pressure. This is a perfect combination of human control and mechanized reliability.

The Filter

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

A filter also improves flavor as it allows for a longer flowering phase. This allows the beans to release their nuances and gives an opportunity for a better extraction.

However it is crucial to remember that even a high-quality filter can make a terrible cup of coffee as the quality of the beans and extraction is still crucial.

It's here that the magic occurs. This is what makes espresso taste so delicious. The grouphead (also called the brewhead) is where you put the portafilter, which is the thingy which you put the grounds of your coffee into while making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight container to create steam. The steam then pushes hot water through the grounds of coffee at high pressure. These kinds of machines are usually cheaper and easier to maintain than pump-driven models. However, they are not as efficient in their capacity to create the perfect conditions for brewing, since they operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.

In recent years, compressed air pump-driven espresso machines have become more popular. They use an air-compressor to force hot water into the ground and are much more mobile than electric steam-driven espresso machines.