How Does Machine Espresso Work?

Machine espresso utilizes precise pressure and amazing filter technology to make the perfect cup of coffee. But how exactly does it work?

Espresso is made by forcing hot water at high 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 implies, the group head is where you insert your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter before controlling the pressure of the extraction. There are several different types of group heads each with its particular advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are built to control the lever. Some are a combination, like the E61. This is a preferred choice for baristas because it offers multiple benefits in one package.

As you can see from the photo above, the group head has a number of notches. You place your portafilter in these notches and then turn the head around to secure it. A gasket made of rubber is placed in the notches to create a seal while you insert your portafilter. The notches allow for precise placement of the portafilter. This is vital for an even extraction.

In addition Bean To Cup Espresso Machine allowing you easily connect your portafilter, Espresso coffee machines the group head is also responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it's always at the correct temperature to extract. It is important to remember that even a slight deviation can make the difference between a decent and a great espresso.

The Pump

The motorized pumps used in rotary espresso machines provide the nine atmospheric bars of pressure required to extract espresso. This is different from manual piston machines which use a lever. The pressure is created by removing 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 are generally less expensive and last longer than piston-driven machines. However, both types of machines can degrade due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can raise prices of even simpler models.

Certain espresso machines remove the pump entirely and make use of steam pressure to make espresso. The drawback is that the same boiler that produces steam also increases the temperature of the water until it reaches boiling and can result in excessive extraction. The machines also need to continually rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines utilize either a vibration or rotary pump. A vibration model employs a rotating disk to generate pressure, whereas the circular model pushes hot liquid through the ground at a rapid speed. Both types of machines can make a great espresso, however the rotary models are quieter and more durable than vibration pumps.

The Boiler

The boiler is the component that heats the water to the optimal temperature for extraction. The resulting steam reaches the portafilter containing the ground espresso coffee and gets funnelled down into the cup. During this process the steam generates enough pressure to push the coffee grounds through. This creates a crema on the top of the espresso. This is one of the hallmarks of a great espresso.

There are three types of espresso makers. They differ in the type of pump they use and how hot the coffee is. There are different ways to control the strength of the brew and the size of cup that can be produced by the machine.

The earliest espresso machines were steam-based. The earliest espresso machine with milk frother machines were steam-type machines. The coffee tasted bitter and burned. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most common espresso maker is a semi-automatic device that has an electric pump. This is what people envision when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans by yourself while the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised quality.

The Filter

Typically, espresso machines utilize filters to separate the grounds of coffee when they pass through the hot water. The filter is also a vital part of the temperature control system since it helps prevent the machine from overheating.

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

It is important to keep in mind that even the most efficient filter can make a bad cup of coffee. The quality of the beans and the extraction, are still crucial.

This is where the magic happens. It's what makes an espresso really taste good. The grouphead (also known as the brewhead) is where you put the portafilter, xilubbs.xclub.tw which is the thingy which you put the grounds of your coffee into when making espresso.

In the steam-driven espresso machine hot water is heated in an airtight container to create steam. This is then pushed through the grounds at high pressure. They are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited in their ability for creating the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.

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