5 Killer Qora's Answers To Machine Espresso
5 Killer Qora's Answers To Machine Espresso
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How Does Machine Espresso Work?
The machine espresso utilizes precision pressure, and filter technology that is mind-blowing to make the coffee you enjoy. What exactly is it?
Espresso is produced by pushing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However the pressure is the primary difference.
The Group Head
The name implies, the group head is the place you place your portafilter when making espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure that results from the extraction. There are a variety of types of group heads each with its distinct advantages and drawbacks. Some focus on temperature stability, some on pre-infusion features, and others are designed to control the lever. Some include a combination such as the E61. This is a very popular choice for baristas as it provides a variety of benefits in a single package.
As you can see from the image above, the group head is fitted with several notches. It is possible to place your portafilter in these notches, then twist the head to lock it. A rubber gasket is located in the notches to create a seal when you insert your portafilter. The notches allow for the precise placement of the portafilter. This is vital for a consistent extraction.
The group head is not just able to allow the portafilter to be inserted easily however it also keeps the same temperature. It does this by cycling hot water through the brew container and around the portafilter, ensuring that it's always at the right temperature to extract. It is important to realize that even a tiny deviation can make the difference between a great and a excellent espresso.
The Pump
Contrary to manual piston machines which use a lever to pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure that are required to extract espresso. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.
Pumps are typically less expensive than piston-driven models, and they tend to last longer, although both types of machines can degrade with overuse and insufficient cleaning. They also increase the complexity of mechanical systems which can result in a high price tag on even the simplest models.
Some espresso machines do away with the pump completely and instead 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 to boiling which can cause excessive extraction. In addition these machines are often required to rebuild their pressure between cups, which takes time and energy.
A majority of espresso machines utilize a rotary or vibration pump. A vibration model employs a vibrating disk to generate pressure, while the Rotary model pushes hot coffee through the ground at a 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 one that heats the water to the perfect temperature for extraction. The steam that is produced reaches the portafilter, which contains the ground espresso coffee, and gets funnelled down into the cup. During this process, steam causes pressure to push through the coffee grounds. This results in a layer of crema that is then poured over. This is one of the hallmarks of a great espresso.
There are three types of espresso machines, each with different types of pumps and the temperature of the brew. There are different ways to control the strength of the brew and the size of cup that can be made by the machine.
The first espresso machines were steam type. They utilized one boiler to make both steam and brew but the pressure they could generate was low - only two bars of atmospheric pressure maximum. The coffee tasted bitter and burned. This is the reason why Milanese producers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most commonly used espresso maker is a semiautomatic machine that has an electric pump. These are the images people have when they think of an espresso maker. With a semi-automatic machine you need to grind the beans and then tamp them by hand, but the pump regulates the flow of water and pressure. This is a great solution that combines human control with mechanised reliability.
The Filter
Typically, espresso machines have filters to separate the coffee grounds as they pass through the hot water. The filter is also an essential element of the temperature control system as it keeps the machine from overheating.
It read more also improves flavor as a filter allows for a longer bloom phase. This allows the beans to release their nuances, and also allows for better extraction.
However it is crucial to remember that even a high-quality filter can produce a bad cup of coffee, since the quality of the beans and extraction are vital.
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 thing you put the coffee grounds into) is placed when you're making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds at a high pressure. They are less expensive and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the ideal brewing conditions, since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.
In recent years, espresso machines powered by compressed air-pump have become increasingly popular. They use an air-compressor to push hot water across the ground, and are more mobile than steam-driven electric espresso machines.