3 Common Causes For Why Your Machine Espresso Isn't Working (And What You Can Do To Fix It)
3 Common Causes For Why Your Machine Espresso Isn't Working (And What You Can Do To Fix It)
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How Does Machine Espresso Work?
The machine espresso is made using precise pressure and filtering technology that is amazing to make the coffee you love. What exactly is it that makes 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 major difference.
The Head of the Group
The group head is the portafilter that is inserted when you are making espresso. It disperses the water into the portafilter, and regulates the pressure of extraction. There are various kinds of group heads, each with their unique advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion capabilities, and still others are designed to control the lever. There are also some that contain a variety of features, like the E61 one, which is the most popular choice among baristas for its ability to offer multiple perks in one package.
As you can see from the image above the head of the group is equipped with several notches. You place your portafilter into these notches and twist the head to lock it. There is also a gasket made of rubber that is a part of the notches, which helps create a seal when you insert your portafilter into the machine. The notches on the head permit a precise placement of the portafilter, which is necessary for an even extraction.
In addition to allowing you to easily place your portafilter in, the group head is 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. It is important to remember that even a few degree difference can make the difference between a decent and a great espresso.
The Pump
Unlike manual piston machines, which rely on a lever to pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure required to extract espresso. This pressure is generated by pumping water through a heat exchanger and then through the ground coffee.
Pumps are typically less expensive than piston-driven machines, and tend to last longer, although both types of machines can be damaged by excessive use and inadequate cleaning. They also make mechanically complex that can lead to the cost of even the most basic models.
Some espresso machines do away with the pump completely and employ steam pressure to create espresso. This can lead to over-extraction as the boiler that makes steam also warms the water to boil. The machines must also continually rebuild their pressure between cups. This takes energy and time.
Many espresso machines utilize an rotary or vibrating pump, with a vibrating model using a vibrating disc that generates the pressure retro espresso machine and a rotary model pushing hot water through the grounds under high speed. Both types of machines are capable of producing excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler heats the water to the ideal temperature for extraction. The resulting steam is then transferred to the portafilter which holds ground espresso beans and is then pumped into the cup. The steam generates enough pressure to push the grounds of coffee through. This creates a layer crema that is then poured over. This is one of the hallmarks of a great espresso.
There are three kinds of espresso makers, and they differ in the type of pump they use and how hot the espresso is. There are a variety of ways that the brew may be controlled as well as the size of the cup that the machine can make.
The first espresso machines were steam type. They had only one boiler to make both brew and steam, however, the pressure they could create was minimal - two bars of atmospheric pressure, at most. This led to the coffee tasting bitter and burnt. The modern espresso machine was invented by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.
The most commonly used espresso maker is a semiautomatic machine that has an electric pump. When people think of espresso machines, they envision these machines. Semi-automatic machines require you to grind and tamp the beans on your own, but the pump regulates the flow of water and pressure. This is a perfect compromise between human control and mechanised accuracy.
The Filter
Espresso machines usually have filters that separate the grounds of the coffee from hot water. The filter is also a vital component of the machine's temp control, as it helps prevent overheating.
It also enhances flavor, as a filter allows for a more prolonged bloom time. This helps the beans to release their flavors and provides an opportunity to improve extraction.
It is important to remember that even the finest filter can result in a bad cup of coffee. The quality of the beans as well as the extraction, are still crucial.
This is where the magic happens, and it's what makes an espresso really taste great. The grouphead, often called the brew head, is the place where the portafilter (the container you place the ground coffee in) is placed when making espresso.
In the steam-driven espresso machine hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at high pressure. These machines are cheaper and easier for the user to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have become more popular. They utilize an air compressor to force hot water through grounds and are much more portable than electric steam-driven machines.