kevinstone52

How Does Machine Espresso Work? Machine espresso employs precise pressure and amazing filter technology to make the delicious coffee we enjoy. But how exactly does it work? To make an espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee, however the main difference lies in the pressure. The Group Head The group head is the portafilter that you put in when making espresso. It disperses the water into the portafilter, and then controls the pressure of the extraction. There are many different kinds of group head, each with their distinct advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion features, and others are designed to control the lever. Some include a combination like the E61. This is a popular choice among baristas because it offers multiple benefits in one package. As you can see in the image above The group head features several notches to place your portafilter before twisting it by hand to lock it in. There is also a gasket of rubber that resides inside the notches, which helps create an airtight seal when you insert your portafilter into the machine. The notches allow for precise placement of your portafilter. This is crucial to ensure an efficient extraction. The group head does not just allow the portafilter to be inserted easily however it also keeps the same temperature. It does this by cycling hot water through the brew pan and around the portafilter to ensure that it is always at the correct temperature for extraction. This is important, as just a few degrees could make the difference between good and excellent espresso. The Pump Unlike manual piston machines, that use a lever to pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure that are required to extract espresso. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee. Pumps tend to be less expensive than piston-driven models, and they tend to last longer, but both types of machines may become damaged due to excessive use and poor cleaning. They also make mechanically complex which can result in an expensive price for even the simplest models. Certain espresso machines utilize steam pressure instead of a pump for brewing espresso. The drawback of this is that the same boiler that produces steam also raises the temperature of the water to boiling which can cause excessive extraction. Additionally these machines are often required to restore their pressure between cups, which requires time and energy. Many espresso machines make use of the rotary or vibration pump, with a vibrating model using a vibrating disc that generates the pressure, and the rotary model pushing hot water through the grounds under high speed. Both types of machines are capable of producing excellent espresso, but the rotary models are quieter and more durable than vibration pumps. The Boiler The boiler is the component that heats the water to the ideal temperature to extract. The steam that is created is then directed to the portafilter, which is the container that holds the espresso coffee grounds. It is then funneled into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This creates a crema on the top of the espresso. This is one of the main characteristics of a good espresso. There are Suggested Web page of espresso machines, each with a different type of pump and the temperature of the brew. There are different ways to control the brew as well as the size of cup that can be made by the machine. The first espresso machines were steam-based. They had one boiler to make steam and brew, but the pressure they could produce was not very high – two bars of atmospheric pressure, at most. This led to the coffee tasting burnt and bitter. The modern espresso machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni. The most popular espresso machine is a semiautomatic that has an electric pump. These are the things people think of when they imagine an espresso machine. With a semi-automatic machine, you have to grind the beans and tamp them by hand, but the pump controls the flow of water and pressure. This is a great compromise between human control and mechanised accuracy. The Filter Typically, espresso machines utilize a filter to separate out the grounds of the coffee as they go through the hot water. The filter is also an essential part of the temperature control system, as it keeps the machine from overheating. Filters also aid in flavor since it allows for the beans to flower for a longer period of time. This allows the beans to release their flavors and provides an opportunity to improve extraction. However it is crucial to keep in mind that even a great filter can produce a bad cup of coffee, because the quality of the beans and extraction is still vital. This is where the magic happens, it's what makes espresso taste great. The grouphead, often referred to as the brewhead, is where the portafilter (the thing you put the coffee grounds into) is placed when making espresso. In the steam-driven espresso machine hot water is heated in an airtight tank to create steam. This then pushes the hot water through the grounds at high pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. They are however limited to create the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars. In recent times, espresso machines powered by a compressed air compressor have become increasingly popular. They use an air compressor to push the hot water through the grounds and are significantly more portable than steam-driven electric machines.