9 Lessons Your Parents Teach You About Machine Espresso
How Does Machine Espresso Work?
machine espresso (mouse click on indexedbookmarks.com) uses precision pressure and mind-blowing filter technology to create the perfect cup of coffee. But 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. However, the pressure is the main difference.
The Group Head
The group head is the portafilter you insert when brewing espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure of the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are designed for stability of temperature while others are specifically designed to handle pre-infusion. Some are designed to control the lever. There are also some that have a combination of features, such as the E61 that is the standard choice for many baristas for its ability to provide multiple benefits in one package.
As you can see from the image above the group head has a number of notches. You place your portafilter in these notches, then turn the head around to secure it. There is also a gasket of rubber that resides inside the notches and helps create an airtight seal after inserting your portafilter into the machine. The notches on the head permit a precise positioning of the portafilter which is necessary to ensure a consistent extraction.
In addition to allowing you easily connect your portafilter, the group head is also responsible for maintaining an even temperature. It does this by circulating hot water through the brew basket, and around the portafilter, ensuring that it's always at the correct temperature for extraction. It is important to realize that even a small variation can mean the difference between a great and a great espresso.
The Pump
The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines which use a lever. The pressure builds by drawing tap water from a reservoir and pumping it through a heat exchanger before being pumped through the ground coffee inside the group head.
Pumps are generally more affordable and last longer than piston-driven machines. However, both types of machines are susceptible to degrading due to overuse and inadequate cleaning. They also increase the complexity of mechanical systems that can lead to the cost of even the most basic models.
Certain espresso machines do away with the pump completely and instead make use of steam pressure to make espresso. This could lead to over-extraction since the boiler that produces steam also heats the water until it comes to a boil. In addition these machines typically have to restore their pressure between cups, which requires time and energy.
A majority of espresso machines utilize a rotary or vibration pump. A vibration model utilizes an oscillating disk to create pressure, whereas a rotary model pushes hot water through the ground at a fast speed. Both types of machines are capable of producing excellent espresso, however Rotary machines are quieter and more durable than vibration pumps.
The Boiler
The boiler is the component that heats water to an ideal temperature for extraction. The steam created reaches the portafilter, which is the container that holds the espresso coffee grounds. It is then pumped into the cup. During this process, the steam creates pressure that pushes through the coffee grounds. This produces a layer of crema on top. This is one of the hallmarks of a great espresso.
There are three kinds of espresso makers, and they differ in the kind of pump they use and how hot the espresso is. There are also different ways that the brew can be controlled and the size of the cup the machine can produce.
The first espresso machines were steam-types. They had only one boiler to make both brew and steam, however, the pressure they could create was minimal - two bars of atmospheric pressure at most. The coffee tasted bitter and burned. This is the reason why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern professional espresso maker machine.
The most well-known home espresso machine machine is a semiautomatic with an electric pump. These are what people imagine when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans yourself The pump, however, regulates the water flow and pressure. This is a great compromise between the human touch and the mechanised quality.
The Filter
Espresso machines usually have a filter that separates the grounds of the coffee from hot water. The filter is also an essential component of the machine's temperature control, since it helps to prevent overheating.
It also improves flavor, since a filter lets you enjoy a longer bloom phase. This lets the beans release their nuances, and improves extraction.
However it is crucial to keep in mind that even a high end espresso machine-quality filter can result in a poor cup of coffee, as the quality of the beans and extraction are important.
It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead (also called the brewhead) is where you put the portafilter - the thingy that you use to put the grounds of coffee into when making espresso.
Steam-driven espresso machines make use of hot water that is heated in an airtight container to produce steam. The steam then pushes hot water into the grounds of the coffee under pressure. These kinds of machines are generally cheaper and easier to maintain than pumps-driven models. They are however limited for creating the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have become more popular. They use an air-compressor to force hot water into the ground and are more mobile than electric steam-driven espresso machines.