How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and incredible filter technology to produce the perfect cup of coffee. What exactly is it?
To make an espresso hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee espresso machines but the major difference is in the pressure.
The Group Head
As the name implies, the group head is the place you place your portafilter while making espresso. It disperses the water into the portafilter, and then regulates the pressure of extraction. There are various kinds of group head, each with their unique advantages and disadvantages. Some are designed for stability in temperature, while others are designed best bean to cup espresso machine handle pre-infusion. Others are made to control the lever. Some have a combination, such as the E61. This is a favorite among baristas due to the fact that it has multiple advantages in one package.
As you can see in the photo above, the group head has numerous notches that you can place your portafilter before twisting it by hand to secure it. A rubber gasket is located in the notches to create a seal when you insert your portafilter. The notches on the head permit an exact location of the portafilter which is necessary to ensure a consistent extraction.
The group head not only allows you to insert your portafilter easily but also maintains the temperature at a constant level. It does this by circulating hot water through the brew container and around the portafilter to ensure that it’s always at the right temperature to extract. This is vital, because even a small difference in temperature can make the difference between a good and excellent espresso.
The Pump
The motorized pumps that are used in espresso machines rotary provide nine atmospheric bar pressure required for espresso extraction. This differs from manual piston machines that rely on levers. The pressure is built by pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be cheaper than piston-driven machines, and tend to last longer, but both types of machine 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.
Certain espresso machines remove the pump entirely and employ steam pressure to create espresso. The downside is that the boiler that produces steam also increases the temperature of the water to the point of boiling and can result in excessive extraction. Additionally these machines are often required to rebuild their pressure between cups, which requires time and energy.
Many espresso machines make use of an rotary or a vibration pump. A vibration model makes use of the vibrating disk to create pressure, while the rotary model pushes hot water through the ground at a fast speed. Both machines can produce excellent espresso but rotary machines are quieter, more durable and less likely to break.
The Boiler
The boiler is what heats the water to the perfect temperature for extraction. The steam that is produced reaches the portafilter that contains the ground espresso coffee, and gets funnelled down into the cup. The steam creates pressure that pushes through the coffee grounds. This creates a crema on the top of the espresso. This is one of the main characteristics of a great espresso.
There are three kinds of espresso machines, each having different pumps and the temperature of the brew. There are different ways to control the brew and the size of the cup that can be made by the machine.
The first espresso machines were steam-type. The first espresso machines were steam-type machines. This led to the coffee machines espresso tasting bitter and burnt. The modern espresso machine was developed by the Milanese makers Luigi Bezzerra & Desiderio Pavoni.
The most well-known espresso machine is a semiautomatic with an electric pump. These are what people imagine when they think of an espresso machine. If you have a semi-automatic machine you have to grind the beans and tamp them by hand. The pump regulates the flow of water and pressure. This is an excellent compromise between human touch and the mechanised accuracy.
The Filter
mini espresso maker machines typically use a filter that separates the grounds of coffee from hot water. The filter is also a vital element of the machine’s temperature control, since it helps to prevent overheating.
A filter also helps with flavor because it allows for an extended flowering time. This allows the beans to release their flavor and also allows for better extraction.
However, it is important to remember that even a good filter could result in a bad cup of coffee, since the quality of the beans and extraction is crucial.
It’s here that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you place the portafilter – the thingy used to place the coffee grounds into, when making espresso.
In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam, which then pushes the hot water through the grounds at high pressure. These kinds of machines are generally cheaper and easier to maintain than pumps-driven models. However, they are not as efficient in their ability to produce the ideal conditions for brewing since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.
In recent years, espresso machines driven by a compressed air pump have become increasingly popular. They use an air compressor to force the hot water through the grounds and are much more portable than steam-driven electric machines.
