16 Must-Follow Facebook Pages To Machine Espresso Marketers How Does Machine Espresso Work?    Machine espresso makes use of precise pressure and mind-blowing filter technology to create the coffee we love. But 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 but the major difference is in the pressure.    The Head of the Group    As the name suggests, the group head is the place you place your portafilter while brewing espresso. It disperses water into the portafilter, and then controls the pressure of the extraction. There are a variety of group heads, each with its own advantages and drawbacks. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Others are made to control the lever. Some include a combination such as the E61. This is a popular choice among baristas due to the fact that it has multiple advantages in a single package.    As you can see in the image above the group head comes with several notches where you place your portafilter before twisting it manually to secure it. A gasket of rubber is situated inside the notches, which helps create a seal while you insert your portafilter. The notches allow for the precise placement of the portafilter. This is crucial for an efficient extraction.    In addition to allowing you to easily connect your portafilter, the group head is also responsible for maintaining a consistent temperature. This is accomplished by cycling hot water around the portafilter, and through the brew-basket, making sure the temperature is always right for extraction. espresso coffee machine is important, as just a few degrees could mean the difference between good and excellent espresso.    The Pump    Unlike manual piston machines, which rely on a lever that pressurize water, rotary espresso machines rely on motorized pumps to provide the nine atmospheric bars of pressure necessary to extract espresso. The pressure builds up by removing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.    Pumps tend to be less expensive than piston-driven machines, and they tend to last longer, however both types of machines could be damaged by excessive use and inadequate cleaning. They also increase the complexity of mechanical systems that can lead to an expensive price for even the simplest models.    Some espresso machines eliminate the pump completely and instead make use of steam pressure to make espresso. This can lead to over-extraction as the boiler that makes steam also heats the water to boil. Additionally these machines typically have to restore their pressure between cups, which requires time and energy.    Many espresso machines employ a vibration or rotary pump, with a vibrating model using a vibrating disc that generates the pressure and rotating models that push hot water through the grounds at high speed. Both machines produce great espresso however rotary machines tend to be more quiet, durable and less likely to break down.    The Boiler    The boiler is the component that heats water to an optimal temperature for extraction. The steam that is produced gets to the portafilter which is the container that holds the espresso coffee grounds. It is then pumped into the cup. During this process the steam causes enough pressure to push the coffee grounds through. This creates a layer crema that is then poured over. This is one of the main characteristics of a great espresso.    There are three kinds of espresso machines, each with different types of pumps and brew temperature. There are also different ways in which the brew could be controlled as well as the size of the cup the machine is capable of making.    The first espresso machines were steam-types. They utilized only one boiler to make steam and brew, however, the pressure they could generate was low - only two bars of atmospheric pressure at the most. The coffee tasted bitter and burnt. This is the reason Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.    The most common espresso maker is a semi-automatic device with an electric pump. These are what people imagine when they imagine 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 great compromise between the human touch and mechanized quality.    The Filter    Espresso machines typically have a filter that separates the grounds of the coffee from hot water. The filter is also a vital part of the machine's temperature control, since it helps to prevent overheating.    A filter also helps with flavor as it allows for an extended flowering time. This helps the beans release their flavors and provides an opportunity to improve extraction.    However, it is important to remember that even a high-quality filter can make a terrible cup of coffee as the quality of the beans and extraction are important.      This is where the magic happens. It's what makes an espresso really taste great. The grouphead, often called the brew head, is the place where the portafilter (the device you put the ground coffee in) is placed when you're making espresso.    In the steam-driven espresso machine hot water is heated in an airtight tank to produce steam, which is then pushed through the grounds at high pressure. These kinds of machines are usually cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to produce the perfect conditions for brewing, as they only operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.    In recent years, espresso machines powered by compressed air-pump have become increasingly popular. They use an air compressor to force hot water through grounds and are significantly more portable than electric steam-driven machines. 

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