10 Facts About Machine Espresso That Can Instantly Put You In A Good Mood
10 Facts About Machine Espresso That Can Instantly Put You In A Good Mood
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How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and incredible filter technology to produce the delicious coffee we enjoy. How exactly does it work?
To make an espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee, but the major difference is in the pressure.
The Head of the Group
The group head is the portafilter that you insert when brewing espresso. It distributes water into the portafilter, and then regulates the pressure during the extraction. There are a variety of group heads each with its own advantages and disadvantages. Some focus on temperature stability, while others on pre-infusion capabilities, and still others are designed to control the lever. There are also some that include a mix of features, such as the E61 one, which is the standard choice for many baristas due to its ability to offer multiple benefits in a single package.
As you can see in the photo above the group head is made up of several notches to place your portafilter and twist it with your hands to secure it. A rubber gasket is located inside the notches to help create a seal when you insert your portafilter. The notches permit precise placement of your portafilter. This is crucial for an efficient extraction.
Apart from allowing you easily insert your portafilter, the group head is also responsible for maintaining an even temperature. It does this by circulating hot water through the brew pan and around the portafilter to ensure that it's always at the correct temperature for extraction. This is important because even a few degrees can mean the difference between excellent and great espresso.
The Pump
Contrary to manual piston machines which use a lever to pressurize water, Rotary espresso machines rely on motorized pumps that provide the nine atmospheric bars of pressure necessary for espresso extraction. This pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger before being pumped through the ground coffee inside the group head.
Pumps tend to be cheaper than piston-driven machines and tend to last longer, but both types of machine can become damaged due to excessive use and poor cleaning. They also create mechanical complexity which can result in costly prices for even the simplest models.
Some espresso machines employ steam pressure instead of a pump to make espresso. This can result in over-extraction because the boiler that makes steam also causes the water to boil. The machines must also constantly rebuild their pressure in between cups. This requires energy and time.
Many espresso machines utilize a vibration or rotary pump, which has a vibration model using a vibrating disc to create pressure and a rotary model pushing hot water through the grounds at high speed. Both machines produce great espresso, but rotary machines are more quiet, durable and less likely to fail.
The Boiler
The boiler is what will heat the water to the perfect temperature to extract. The steam that is created gets to the portafilter which holds the espresso grounds. It is then poured into the cup. In this process, the steam creates pressure and pushes through the coffee grounds. This creates a crema on top of the espresso. This is one of the main characteristics of a great espresso.
There are three distinct types of espresso machines, each having distinct pumps and the temperature of the brew. There are various ways in which the brew can be controlled and the dimensions of the cup the maker can create.
The first espresso machines were steam types. The first espresso machines were steam types. The coffee tasted bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most popular espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they think of these machines. Semi-automatic machines require you to grind and tamp the beans yourself however the pump controls the water flow and pressure. This is a great compromise between the human touch and the mechanised consistency.
The espresso and filter coffee machine Filter
Espresso machines typically have a filter that separates the coffee grounds from the hot water. The filter is also an essential component of the temperature control system since it helps prevent the machine from overheating.
A filter also improves flavor because it allows for a longer flowering period. This helps the beans let their nuances out and provides an opportunity to improve extraction.
However it is crucial to remember that even a good filter could result in a bad cup of coffee, because the quality of the beans and extraction is vital.
It's here that the magic happens. This is the reason why espresso tastes so good. The grouphead, sometimes referred to as the brew head, is where the portafilter (the thingy you put the coffee ground into) is located when you're making espresso.
In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. Steam is then pushed through the grounds at high pressure. These types of machines tend to be cheaper and easier to maintain than pumps-driven models. However, they are limited in their ability to create the ideal brewing conditions, because they operate at 1-1.5 bars of pressure. The perfect shot requires 9-10 bar.
In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They utilize an air compressor to force hot water into the grounds and are more portable than electric steam-driven machines.