Are You Sick Of Machine Espresso? 10 Inspirational Ideas To Bring Back Your Love
Are You Sick Of Machine Espresso? 10 Inspirational Ideas To Bring Back Your Love
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How Does Machine Espresso Work?
Machine espresso uses precision pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly does it work?
To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee but the major difference is in the pressure.
The Group Head
As the name suggests the group head is the place you place your portafilter while brewing espresso. It is responsible for dispersing the water into the portafilter and then controlling the pressure that results from the extraction. There are many different kinds of group heads each with its unique advantages and disadvantages. Some are designed to provide stability of temperature while others are specifically designed to handle pre-infusion. Others are made to control the lever. Some come with a range of features, like the E61, which is considered to be the most popular among baristas for its ability to offer multiple perks in a single package.
As you can see in the image above The group head features numerous notches that you can place your portafilter and twist it manually to secure it. A gasket made of rubber is placed within the notches to create a seal when you insert your portafilter. The notches on the head allow for an exact position of the portafilter which is crucial to ensure a consistent extraction.
Apart from allowing you easily place your portafilter in, the group head is responsible for maintaining a consistent temperature. It does this by circulating hot water through the brew basket, and around the portafilter, making sure that it's always at the right temperature for extraction. It is crucial to keep in mind that even a small difference can make the difference between a good and a excellent espresso.
The Pump
Contrary to manual piston machines that use a lever to pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure necessary to extract espresso. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.
Pumps are typically less expensive and last longer than piston-driven machines. However, both kinds of machines may degrade because of excessive use and poor cleaning. Pumps are also more complex mechanically, which can raise the cost of even the simpler models.
Certain espresso machines can eliminate the pump entirely and use steam pressure to brew espresso. The disadvantage of this is that the boiler that produces steam also raises the temperature of the water to boiling, which can lead to excessive extraction. The machines also need to constantly rebuild their pressure between cups. This takes energy and time.
Many espresso machines utilize a vibration or rotary pump, with a vibrating model using a rotating disc to generate the pressure and an rotary model that pushes hot water through the grounds website at high speed. Both types of machines can produce an excellent espresso, but the rotary pumps are quieter, and more durable than vibration pumps.
The Boiler
The boiler is the component that heats the water to the ideal temperature for extraction. The resultant steam then reaches the portafilter that contains ground espresso beans and is then pumped into the cup. During this process the steam causes enough pressure to push the grounds of coffee through. This results in a layer crema on top. This is the hallmark of a good espresso.
There are three distinct types of espresso machines, each having different pumps and brew temperature. There are a variety of ways in which the brew can be controlled and the size of the cup the machine is capable of making.
The earliest espresso machines were steam types. They had one boiler to create steam and brew, however the pressure they were able to generate was low - only two bars of atmospheric pressure at the most. The coffee tasted bitter and burned. This is why Milanese makers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most popular espresso machine is a semiautomatic model with an electric pump. When people think of espresso machines, they think of these machines. 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 great compromise between human control and mechanised reliability.
The Filter
Espresso machines usually use filters that separate the grounds of the coffee from the hot water. The filter is also an important component of the temperature control system as it prevents the machine from overheating.
A filter also helps with flavor since it allows for a longer flowering period. This lets the beans release their nuances, and also allows for better extraction.
However, it is important to keep in mind that even a good filter could result in a bad cup of coffee as the quality of the beans and extraction are crucial.
This is where the magic happens, it's what makes espresso taste great. The grouphead (also called the brewhead) is where you put the portafilter - the thingy that you use to put the coffee grounds in, when making espresso.
Steam-driven espresso machines make use of hot water heated in an airtight container to create steam. The steam then pushes hot water through the grounds of the coffee under pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. They are however limited in their ability for creating the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to push hot water through the ground and are more mobile than electric steam-driven espresso machines.