A Productive Rant About Machine Espresso
A Productive Rant About Machine Espresso
Blog Article
How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and mind-blowing filter technology to create the coffee we love. How exactly does it work?
To make an espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee, but the difference is in the pressure.
The Group Head
The group head is the portafilter is inserted when you are making espresso. It disperses the water into the portafilter, and then controls the pressure of the extraction. There are various kinds of group heads each with its unique advantages and drawbacks. Some are specifically designed for the stability of temperature while some are specifically designed to handle pre-infusion. Others are made to control the lever. Some have a combination, like the E61. This is a popular choice among baristas since it provides multiple benefits in a single package.
As you can see in the image above the group head is fitted with a variety of notches. You can place your portafilter in these notches, then twist the head to lock it. There is also a rubber gasket which is located inside the notches, which helps create a seal when you insert your portafilter into the machine. The notches permit the precise placement of the portafilter. This is crucial for an efficient extraction.
Aside from allowing you to easily insert your portafilter, the group head is responsible for maintaining an even temperature. 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 vital, because even a few degrees can make the difference between a good and 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 for espresso extraction. The pressure builds by removing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.
Pumps tend to be cheaper than piston-driven models, and they tend to last longer, but both types of machines may become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which could increase prices of even most basic models.
Certain espresso machines utilize steam pressure instead of a pump in order to brew espresso. This can result in over-extraction because the boiler that makes steam also heats the water to boil. Additionally the machines often have to restore their pressure between cups, which requires time and energy.
Many espresso machines use the rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, whereas the rotary model pushes hot water through the ground at a fast speed. Both machines can make great 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 produced will eventually reach the portafilter, which is a container for espresso grounds. The steam is then channeled into the cup. The steam generates enough pressure to push the grounds of the coffee through. This results in a layer of crema that is then poured over. This is the hallmark of a good 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 to control the brew as well as the size of the cup that can be produced by the machine.
The first espresso machines were steam-types. They employed only one boiler to make both brew and steam, but the pressure they could produce was very low - just two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. The modern espresso machine was invented by the Milanese manufacturers Luigi Bezzerra & Desiderio Pavoni.
The most common espresso maker is a semi-automatic machine with 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 however the pump controls the flow of water and pressure. This is an excellent compromise between human touch and the mechanised quality.
The Filter
Typically, espresso machines have a filter to separate out the more info coffee grounds as they pass through the hot water. The filter is also a vital element of the machine's temperature control, as it helps prevent overheating.
A filter also improves flavor as it allows for a longer flowering phase. This allows the beans to release their nuances, and also allows for better extraction.
It is important to remember that even the finest filter could result in a poor cup of coffee. The quality of the beans and the extraction process remain crucial.
This is where the magic happens. It's what makes an espresso really taste good. The grouphead (also known as the brewhead) is where you put the portafilter, which is the thingy that you use to put the grounds of coffee into while making espresso.
Steam-driven espresso machines make use of hot water that is heated in an airtight container to make steam. The steam then pushes hot water through the grounds of coffee under high pressure. They are less expensive and easier to maintain than pumps-driven models. However, they are limited in their ability to produce the perfect conditions for brewing, because they operate at 1-1.5 bars of pressure, while the perfect shot requires 9-10 bars.
In recent years, espresso machines powered by a compressed air pump have become increasingly popular. They use an air-compressor to push hot water through the ground. They are also more mobile than steam-driven electric espresso machines.