10 Facts About Machine Espresso That Make You Feel Instantly An Optimistic Mood
10 Facts About Machine Espresso That Make You Feel Instantly An Optimistic Mood
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How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and mind-blowing filter technology to make the perfect cup of coffee. What exactly is it that makes it work?
Espresso is produced by pushing hot water under pressure through finely-ground coffee. The process is similar to that of making drip coffee. However the pressure is the major difference.
The Group Head
The name implies the group head is where you put your portafilter in when making espresso. It distributes water into the portafilter and regulates the pressure of the extraction. There are several different types of group heads each with its distinct advantages and disadvantages. Some are designed for stability in temperature, while others are designed 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 one package.
As you can see from the picture above the head of the group is fitted with a variety of notches. You can place your portafilter in these notches, then twist the head to secure it. A rubber gasket is located within the notches to create a seal as you insert your portafilter. The notches allow for an exact placement of the portafilter. This is crucial for a consistent extraction.
The group head not only lets the portafilter to be inserted easily however, it also keeps a constant temperature. This is achieved by cycling hot water around the portafilter and through the brew-basket, making sure the temperature is always right for extraction. It is crucial to keep in mind that even a slight variation can mean the difference between a good and excellent espresso.
The Pump
The motorized pumps in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines which use levers. This pressure is built up by pumping water through a heat exchanger and then through the ground coffee.
Pumps tend to be less expensive and last for longer than piston-driven machines. However, both types of machines may degrade because of frequent use and insufficient cleaning. Pumps are also more complex mechanically, which can increase prices of even most basic models.
Certain espresso machines remove the pump completely and use steam pressure to brew espresso. The drawback of this is that the boiler that produces steam also raises the temperature of water to the point of boiling which can cause over-extraction. These machines also have to constantly rebuild their pressure between cups. This requires energy and time.
Many espresso machines employ either a rotary or vibration pump, with a vibrating model that uses a vibrating disc that generates the pressure, and the rotary model pushing hot water through the grounds at high speed. Both machines can make excellent espresso, but rotary machines are more quiet, durable and less likely to fail.
The Boiler
The boiler is what heats the water to the perfect temperature for extraction. The resulting steam is then transferred to the portafilter, which contains the ground espresso coffee and is then pumped down into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This results in a whipped-up top of the espresso. This is a sign of a good espresso.
There are three types of espresso makers, which differ in the kind of pump they use and how hot the brew is. There are different ways in which the brew can be controlled, as well as the dimensions of the cup the machine can produce.
The earliest espresso machines were steam types. They employed only one boiler to make steam and brew, however the pressure they were able to generate was low - only two bars of atmospheric pressure, at most. The coffee tasted bitter and burnt. This is why the Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most popular espresso maker is a semi-automatic device with an electric pump. These are the images people have when they think of an espresso machine. espresso coffee machines uk If you have a semi-automatic machine you grind the beans and then tamp them yourself but the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanized consistency.
The Filter
Espresso machines typically use filters that separate the coffee grounds from the hot water. The filter is also a vital element of the machine's temperature control, as it prevents overheating.
It also enhances flavor, since a filter lets you enjoy a longer bloom time. This helps the beans release their flavors and provides an opportunity for a better extraction.
It is important to keep in mind that even the best filter can produce a bad cup of coffee. The quality of the beans and the extraction, remain vital.
This is where the magic happens, it's what makes espresso taste great. The grouphead (also called the brewhead) is where you place the portafilter, which is the thingy used to place the grounds of your coffee into when making espresso.
Steam-driven espresso machines make use of hot water that is heated inside an airtight container to make steam. The steam then pushes hot water into the coffee grounds under high pressure. They are less expensive and are easier for the user to maintain than pumps-driven models. However, they are limited in their ability to create the perfect brewing conditions because they operate at 1-1.5 bars of pressure. However, 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 across the ground and are much more mobile than electric steam-driven espresso machines.