12 Companies Are Leading The Way In Machine Espresso
12 Companies Are Leading The Way In Machine Espresso
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How Does Machine Espresso Work?
The machine espresso uses precision pressure, and a filtering technology that is amazing to make the coffee you love. What exactly is it?
Espresso is made by forcing hot water at high pressure through finely-ground coffee. The process is similar to that of making drip coffee. However, the pressure is the major difference.
The Head of the Group
As the name implies the group head is the place you place your portafilter when making espresso. It is responsible for dispersing water into the portafilter and controlling the pressure of the extraction. There are numerous kinds of group heads, each with its own advantages and drawbacks. Some are specifically designed for temperature stability while others are designed to handle pre-infusion. Some are designed to control the lever. There are also some that include a mix of features, such as the E61 that is the standard choice for many baristas because of its ability to provide multiple benefits in a single package.
As you can see in the photo above the group head is made up of several notches to put your portafilter, then twist it manually to lock it in. There is also a gasket made of rubber that resides inside the notches and helps create an airtight seal when you insert your portafilter into the machine. The notches allow for precise placement of your portafilter. This is vital for an efficient extraction.
The group head not only lets you to insert your portafilter easily, but it also maintains the same temperature. This is accomplished by cycling hot water around the portafilter and through the brew basin, ensuring the temperature is always right to extract the coffee. It is important to remember that even a small differences can make the distinction between a good and great espresso.
The Pump
The motorized pumps that are used in espresso machines that rotate provide the nine atmospheric bar pressure that is required for espresso extraction. This is different from manually operated piston machines that employ levers. The pressure is created by drawing tap water from a reservoir and pumping it through a heat exchanger prior being pumped through the ground coffee inside the group head.
Pumps are generally less expensive and last for longer than piston-driven machines. However, both types of machines can degrade due to overuse and insufficient cleaning. Pumps are also more complex mechanically, which can raise the price of even the simpler models.
Certain espresso machines utilize steam pressure instead of a pump to brew espresso. This can result in over-extraction because the boiler that makes steam also heats the water to boil. The machines must also constantly rebuild their pressure between cups. This requires energy and time.
Many espresso machines make use of the rotary or vibration pump, which has a vibration model that uses a vibrating disc to generate the pressure and rotating models that push hot water through the grounds under high speed. Both machines can produce excellent espresso, however rotary machines are more stable, quieter and less likely to fail.
The Boiler
The boiler is what is used to heat the water to the perfect temperature for extraction. The resulting steam is then transferred to the portafilter that contains the ground espresso coffee, and gets funnelled down into the cup. During this process, steam creates pressure that pushes through the grounds of the coffee. This results in a whipped-up top of the espresso. This is one of the hallmarks of a good espresso.
There are three distinct types of espresso machines, each with a different type of pump and the temperature of the brew. There are also different ways that the brew may be controlled, as well as the dimensions of the cup the machine is capable of making.
The first espresso machines were steam type. They utilized only one boiler to make both steam and brew but the pressure they could generate was low - only two bars of atmospheric pressure at the most. This led to the coffee tasting burnt and bitter. This is why the Milanese makers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most popular espresso maker is a semi-automatic one with an electric pump. These are what people imagine when they think of an espresso maker. If you have a semi-automatic machine you grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a great compromise between the human touch and the mechanised quality.
The Filter
Typically, espresso machines use filters that separate the grounds of coffee as they move through the hot water. The filter is also an essential element of the temperature control system, as it prevents the machine from overheating.
A filter also improves flavor as it allows for an extended flowering time. This helps the beans to release their flavors and provides an opportunity for a 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, remain crucial.
It's here that the magic takes place. This is the reason why espresso tastes so good. The grouphead (also called the brewhead) is where you put the portafilter, which is the thingy used to place the grounds of your coffee into while making espresso.
Steam-driven espresso machines use hot water heated in an airtight container to produce steam. The steam then moves hot water through the grounds of coffee under high more info pressure. These machines are cheaper and are easier for the user to maintain than pumps-driven models. They are however limited to create the perfect conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have become more popular. They utilize an air compressor to push hot water into the grounds and are more portable than electric steam-driven machines.