The No. 1 Question That Anyone Working In Machine Espresso Needs To Know How To Answer
The No. 1 Question That Anyone Working In Machine Espresso Needs To Know How To Answer
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How Does Machine Espresso Work?
The machine espresso utilizes precise pressure and filtering technology that is amazing to make the coffee you enjoy. How exactly does it work?
Espresso is made by pushing hot water under high pressure through finely ground coffee. The process is similar to making drip coffee, however the main difference lies in the pressure.
The Head of the Group
The group head is the portafilter you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter and then controlling the pressure of the extraction. There are several different types of group heads each with its unique advantages and disadvantages. Some are designed for temperature stability while others are built to handle pre-infusion. Some are designed to control the lever. Some come with a combination of both, such as the E61. This is a preferred choice for baristas since it provides multiple advantages in a single package.
As you can see from the above photo, the group head is fitted with a variety of notches. You can place your portafilter into these notches and twist the head to secure it. A rubber gasket is located in the notches to make a seal when you insert your portafilter. The notches on the head permit an exact position of the portafilter which is vital to ensure a consistent extraction.
In addition to allowing you to easily insert your portafilter, the group head is also responsible for maintaining a consistent temperature. This is achieved by cycling hot water around the portafilter and through the brew basin, ensuring that the temperature is at the right level to extract the coffee. This is important, as even a small difference in temperature can make the difference between a good and great espresso.
The Pump
The motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure needed to extract espresso. This differs from manual piston machines that rely on a lever. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.
Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines can degrade because of excessive use and insufficient cleaning. They also add mechanical complexity and can lead to costly prices for even the most basic models.
Some espresso machines remove the pump entirely and use steam pressure to brew espresso. This can lead to over-extraction as the boiler that produces steam also warms the water to boil. Additionally these machines typically have to restore their pressure between cups, which requires time and energy.
Many espresso machines make use of either a vibration or rotary pump. A vibration model employs the vibrating disk to create pressure, whereas the rotary model pushes hot water through the ground at a fast speed. Both machines can make great espresso but rotary machines are more quiet, durable and less likely to fail.
The Boiler
The boiler is the element that heats water to an optimal temperature to extract. The resultant steam then reaches the portafilter containing the ground espresso and gets funnelled down into the cup. The steam is able to create enough pressure to push the grounds of coffee through. This creates a crema on the top of the espresso. This is the hallmark 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 a variety of ways in which the brew can be controlled, as well as the size of the cup that the machine can make.
The earliest espresso machines were steam types. The earliest espresso machines were steam-type machines. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was invented by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most popular espresso maker is a semi-automatic one with an electric pump. These are the images people have when they think of an espresso espresso machines for home machine. With a semi-automatic espresso machine, you grind the beans and then tamp them by hand. However, the pump is able to regulate the flow of water and pressure. This is an excellent compromise between human touch and the mechanised accuracy.
The Filter
Typically, espresso machines utilize filters that separate the grounds of coffee as they move through the hot water. The filter is also an essential component of the machine's temperature control, as it helps prevent overheating.
A filter also improves flavor, as it permits an extended flowering time. This allows beans to let their nuances out and provides an opportunity for a better extraction.
However, it is important to keep in mind that even a great filter could result in a bad cup of coffee, since the quality of the beans and extraction is still important.
This is where the magic happens, and it's what makes an espresso really taste good. The grouphead (also known as the brewhead) is where you place the portafilter, the device that you use to put the coffee grounds into, when 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 into the coffee grounds under high pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. However, they are not as efficient in their ability to provide the perfect brewing conditions as they only operate at 1-1.5 bars of pressure. However, the perfect shot requires 9-10 bars.
In recent years, compressed air pump-driven espresso machines have been gaining popularity. They utilize an air compressor to push hot water through the grounds and are more portable than electric steam-driven machines.