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How Does Machine Espresso Work?

Machine espresso uses precision pressure and incredible filter technology to produce the coffee we love. How exactly does it work?

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

The Group Head

As the name suggests the group head is the place you insert your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter, and controlling the pressure of the resulting extraction. There are numerous kinds of group heads each with distinct advantages and disadvantages. Some focus on temperature stability, some on pre-infusion capabilities, while others are designed to control the lever. There are also some that come with a range of features, like the E61, which is considered the most popular choice among baristas due to its ability to offer multiple benefits in a single package.

As you can see in the photo above the head of the group is equipped with several notches. It is possible to place your portafilter in these notches, then twist the head to lock it. A gasket made of rubber is placed in the notches to make a seal when you insert your portafilter. The notches on the head permit an exact position of the portafilter which is vital for a consistent extraction.

The group head is not just able to allow you to put in your portafilter easily however it also keeps a constant temperature. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it is always at the right temperature for extraction. It is important to realize that even a few degree difference can make the difference between a great and a great espresso.

The Pump

Contrary to manual piston machines which use a lever to pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure necessary to extract espresso. The pressure builds by drawing tap water from a reservoir and pumping it through a heat exchanger prior to being pushed through the ground coffee in the group head.

Pumps tend to be less expensive than piston-driven models, and they tend to last longer, although both types of machine can become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase the cost of even the simplest models.

Certain espresso machines can eliminate the pump completely and make use of steam pressure to make espresso machine black friday (mouse click on Telegra). This can lead to over-extraction as the boiler that produces steam also warms the water to boil. These machines also have to continuously rebuild their pressure between cups. This requires energy and time.

Many espresso machines employ a vibration or rotary pump, which has a vibration model using a vibrating disc to generate the pressure, and a rotary model pushing hot water through the grounds under high speed. Both machines produce great espresso however rotary machines tend to be quieter, more durable and less likely to fail.

The Boiler

The boiler makes the water warm to the ideal temperature for extraction. The steam that is produced reaches the portafilter that contains the ground espresso coffee and is then funneled down into the cup. In this process, the steam causes pressure to push through the coffee grounds. This results in a layer crema on top. This is the hallmark of a good espresso.

There are three types of mini espresso maker makers, and they differ in the kind of pump they use and how hot the brew is. There are also different ways that the brew can be controlled and the size of the cup the maker can create.

The first espresso machines were steam-type. They had one boiler to create steam and brew, but the pressure they could produce was not very high - two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. The modern espresso machine was developed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic device that has an electric pump. When people think of espresso machines, they think of these machines. If you have a semi-automatic machine you need to grind the beans and tamp them by hand, but the pump regulates the flow of water and pressure. This is a perfect combination of human control and mechanised accuracy.

The Filter

Typically, best espresso maker machines use filters that separate the grounds of the coffee and espresso machine as they go through the hot water. The filter is also a crucial part of the temperature control system because it stops the machine from overheating.

A filter also improves flavor because it allows for a longer flowering period. This allows the beans to release their flavor and gives an opportunity to improve extraction.

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

It's in this area that the magic happens. This is the reason why espresso tastes so delicious. The grouphead, sometimes referred to as the brew head, is where the portafilter (the thing you put the ground coffee in) is located when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight container to create steam. Steam then pushes the hot water through the grounds with high pressure. These kinds of machines are typically less expensive and easier to maintain than pump-driven models. They are however limited in their ability for creating the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9 bar espresso machine-10 bars.

In recent years, compressed air-driven espresso machines have been gaining popularity. They utilize an air compressor to force the hot water through the grounds and are more portable than steam-driven electric machines.