How Does Machine Espresso Work?
The machine espresso utilizes precision pressure, and filtering system that is awe-inspiring to make the coffee you enjoy. How does it work exactly?
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
The name implies, the group head is where you place your portafilter when brewing espresso. It is responsible for dispersing the water into the portafilter and controlling the pressure of the resulting extraction. There are numerous kinds of group heads, each with its own advantages and disadvantages. Some are focused on temperature stability, while others on pre-infusion options, and others are designed to control the lever. Some include a combination like the E61. This is a popular choice among baristas due to the fact that it has multiple advantages in one package.
As you can see from the picture above, the group head is fitted with a variety of notches. The portafilter is placed in these notches and then turn the head around to secure it. A gasket made of rubber is placed within the notches to make a seal when you insert your portafilter. The notches on the head permit a precise location of the portafilter which is necessary for an efficient extraction.
In addition to allowing you effortlessly insert your portafilter the group head is responsible to ensure that the temperature remains even. It does this by circulating hot water through the brew basket, and around the portafilter to ensure that it is always at the correct temperature for extraction. This is crucial, since just a few degrees could make the difference between excellent and great espresso.
The Pump
Contrary to manual piston machines which rely on a lever to pressurize water, the rotary espresso machines use motorized pumps to deliver the nine atmospheric bars of pressure required to extract espresso. The pressure is created 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, but both types of machines may become damaged due to excessive use and poor cleaning. Pumps are also more complicated mechanically, which could increase the cost of even the simple models.
Certain espresso machines utilize steam pressure instead of a pump in order to brew espresso. This can cause over-extraction because the boiler that makes steam also warms the water to boil. The machines also need
best bean to cup espresso machine constantly rebuild their pressure between cups. This takes energy and time.
A large majority of espresso machines employ a rotary or vibration pump. A vibration model uses a vibrating disk to generate pressure, while the circular model pushes hot liquid through the ground at a rapid speed. Both machines can produce excellent espresso however rotary machines tend to be more quiet, durable and less likely to break down.
The Boiler
The boiler is what is used to heat the water to the perfect temperature to extract. The steam created gets 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 causes enough pressure to push the coffee grounds through. This results in a crema on the top of the espresso. This is one of the main characteristics of a good
retro espresso maker.
There are three kinds of
decent espresso machine makers, which differ in the type of pump they employ and the degree of heat that the espresso is. There are a variety of ways in which the brew can be controlled, as well as the size of the cup the machine can produce.
The first espresso machines were steam-type. They utilized one boiler to make both steam and brew, but the pressure they could produce was very low - just two bars of atmospheric pressure at most. This resulted in the coffee tasting bitter and burnt. The modern espresso machine was designed by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most popular espresso maker is a semi-automatic machine that has an electric pump. When people think of
espresso machine with Milk frother (
www.mazafakas.com) machines, they envision these machines. With a semi-automatic machine, you have to grind the beans and then tamp them by hand, but the pump provides regulated water flow and pressure. This is a great compromise between the human touch and mechanized accuracy.
The Filter
Espresso machines typically use filters that separate the coffee grounds from the hot water. The filter is also a vital component of the machine's temperature control, since it stops overheating.
A filter can also help with flavor because it allows for a longer flowering period. This allows beans to release their nuances and gives an opportunity for a better extraction.
However, it is important to keep in mind that even a top 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 the thing that makes espresso taste great. The grouphead (also known as the brewhead) is where you place the portafilter, the thingy which you put the grounds of coffee into while making espresso.
In an
retro espresso machine machine that is driven by steam, hot water is heated in an airtight tank to create steam. Steam then pushes the hot water through the grounds under high pressure. These types of machines are typically cheaper and easier to maintain than pumps-driven models. They are however limited in their ability to create the perfect conditions for brewing since 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 pump have become increasingly popular. They use an air-compressor to force hot water into the ground and are more mobile than steam-driven electric espresso machines.