femalecar57

How Does Machine Espresso Work? Machine espresso makes use of precise pressure and mind-blowing filter technology to create the perfect cup of coffee. What exactly is it that makes it work? Espresso is made by forcing hot water under high pressure through finely ground coffee. The process is similar to making drip coffee, but the key difference is in the pressure. The Head of the Group The name implies the group head is the place you place your portafilter when brewing espresso. It disperses the water into the portafilter and regulates the pressure of extraction. There are several different types of group heads each with its unique advantages and disadvantages. Some are designed to provide stability of temperature while others are built to handle pre-infusion. automatic espresso machine are built to control the lever. Some come with a combination of both, such as the E61. This is a very popular choice for baristas due to the fact that it has multiple benefits in one package. As you can see in the photo above The group head features many notches in which you can put your portafilter, then twist it manually to secure it. A gasket of rubber is situated within the notches to create a seal when you insert your portafilter. The notches on the head permit an exact positioning of the portafilter which is vital for an efficient extraction. The group head does not just allow the portafilter to be inserted easily but also maintains a constant temperature. This is accomplished by cycling hot water around the portafilter, and through the brew basin, ensuring the temperature is always right for extraction. It is important to note that even a slight difference can make the difference between a great and a great espresso. The Pump The motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines which use a lever. This pressure is generated by pumping water through a heat-exchanger and then through the ground coffee. Pumps are generally less expensive and last longer than piston-driven machines. However, both types of machines are susceptible to degrading because of frequent use and inadequate cleaning. Pumps are also more complex mechanically, which can increase the cost of even the most basic models. Some espresso machines remove the pump completely and instead use steam pressure to brew espresso. This can lead to over-extraction as the boiler that produces steam also heats the water to boil. These machines also have to constantly rebuild their pressure between cups. This requires energy and time. Many espresso machines make use of either a vibration or rotary pump. A vibration model uses a vibrating disk to generate pressure, whereas a rotating model pushes hot water through the ground at a fast speed. Both types of machines are capable of producing excellent espresso, but rotary machines are quieter and more durable than vibration pumps. The Boiler The boiler is the part that heats water to the optimal temperature for extraction. The steam that is produced reaches the portafilter, which is a container for espresso grounds. It is then funneled into the cup. The steam is able to create enough pressure to push the coffee grounds through. This results in a crema on top of the espresso. This is a hallmark of a great espresso. There are three kinds of espresso makers, which differ in the type of pump they employ and how hot the espresso is. There are different ways that the brew may be controlled, as well as the size of the cup that the maker can create. The first espresso machines were steam-types. They employed only one boiler to make both steam and brew, but the pressure they could produce was not very high – two bars of atmospheric pressure, at most. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was invented by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni. The most common espresso machine is a semiautomatic model with an electric pump. These are the images people have when they think of an espresso machine. Semi-automatic machines require you to grind and tamp the beans by yourself, but the pump regulates the water flow and pressure. This is a fantastic combination of human control and mechanized consistency. The Filter Espresso machines usually use a filter that separates the grounds of the coffee from hot water. The filter is also an important element of the temperature control system, as it prevents the machine from overheating. A filter also improves flavor since it allows for a longer flowering phase. This allows the beans to release their flavors, and also allows for better extraction. However, it is important to keep in mind that even a top filter could result in a bad cup of coffee, because the quality of the beans and extraction are important. It's in this area that the magic takes place. This is what makes espresso taste so good. The grouphead, also called the brewhead, is where the portafilter (the thingy you put the coffee grounds into) sits when you're making espresso. In a steam-driven espresso machine, hot water is heated in an airtight container to create steam. This is then pushed through the grounds with high pressure. These types of machines are usually less expensive and simpler to maintain than pumps-driven models. However, they are not as efficient in their ability to create the ideal conditions for brewing since they are only operating at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars. In recent years, compressed-air-pump-driven espresso machines have become more popular. They use an air-compressor to push hot water across the ground. They are also more mobile than steam-driven electric espresso machines.