(Image: https://cdn.freshstore.cloud/offer/images/778/2223/quest-36569-espresso-coffee-machine-with-milk-frother-1-2l-water-tank-and-drip-tray-steam-ready-and-temperature-indicator-for-ground-coffee-beans-15-bars-of-pressure-2223.jpg)How Does Machine Espresso Work?
Machine espresso makes use of precise pressure and amazing filter technology to make the perfect cup of coffee. How exactly does it work?
Espresso is produced by pushing hot water at high pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the primary difference.
The Head of the Group
The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing water into the portafilter and controlling the pressure of the resulting extraction. There are many different types of group heads, each with its own advantages and drawbacks. Some are specifically designed for the stability of temperature while some are built to handle pre-infusion. Others are built to control the lever. Some are a combination, like the E61. This is a preferred choice for baristas since it provides multiple benefits in one package.
As you can see in the above image the group head is made up of several notches where you place your portafilter and then twist it manually to secure it. There is also a gasket of rubber which is located inside the notches, which helps create an airtight seal when you insert your portafilter into the machine. The notches allow for precise placement of the portafilter. This is crucial to ensure a consistent extraction.
In addition to allowing you effortlessly insert your portafilter the group head is responsible to ensure that the temperature remains even. This is accomplished by cycling hot water around the portafilter and through the brew-basket, making sure the temperature is always right to extract the coffee. It is important to remember that even a few degree difference can make the difference between a great and a great espresso.
The Pump
In contrast to manual piston machines which rely on a lever to pressurize water, the rotary espresso machines use motorized pumps to provide the nine atmospheric bars of pressure needed to extract espresso. The pressure builds up by drawing tap water from a reservoir, and pumping it through a heat exchanger prior being pushed through the ground coffee inside the group head.
Pumps are typically less expensive than piston-driven models, and they tend to last longer, however both types of machines can become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, and can add to the price of even the simplest models.
Some espresso machines eliminate the pump completely and use steam pressure to brew espresso. The drawback is that the same boiler that produces steam also raises the temperature of water to the point of boiling and can result in over-extraction. In addition these machines typically have to rebuild their pressure between cups, which requires time and energy.
Many espresso machines utilize either a rotary or vibration pump, with a vibration model using a rotating disc that generates the pressure and the rotary model pushing hot water through the grounds under high speed. Both machines can produce excellent espresso, but rotary machines are quieter, more durable and less likely to break.
The Boiler
The boiler is the one that heats the water to a temperature that is ideal for extraction. The resulting steam reaches the portafilter containing the ground espresso coffee and is then pumped down into the cup. During this process, the steam creates pressure and pushes through the grounds of the coffee. This results in a crema on the top of the espresso. This is one of the hallmarks of a great espresso.
There are three kinds of espresso machine black friday makers, and they differ in the type of pump they use and the degree of heat that the brew is. There are also different ways in which the brew could be controlled and the size of the cup the maker can create.
The first espresso machines were steam-type. The first espresso machines were steam types. This resulted in the coffee tasting bitter and burnt. This is why the Milanese producers Luigi Bezzerra and Desiderio Pavoni invented the modern espresso machine.
The most commonly used espresso maker is a semi-automatic machine that has an electric pump. These are the images people have when they think of an espresso maker. With a semi-automatic espresso machine, you grind the beans and tamp them yourself but the pump is able to regulate the flow of water and pressure. This is an excellent combination of human control and mechanized accuracy.
The Filter
Espresso machines typically use a filter that separates the grounds of coffee from hot water. The filter is also a vital component of the temperature control system, as it prevents the machine from overheating.
A filter can also help with flavor, as it permits a longer flowering period. This lets the beans release their flavors, and allows for a better extraction.
It is important to keep in mind that even the finest filter can result in a bad cup of coffee. The quality of the beans and the extraction process remain vital.
It's here that the magic happens. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you place the portafilter, the thingy which you put the grounds of coffee into when making espresso.
In an espresso coffee machine for home machine that is driven by steam, hot water is heated in an airtight tank to produce steam, which then pushes the hot water through the grounds at high pressure. These types of machines tend to be less expensive and easier to maintain than pump-driven models. However, they are limited in their capacity to create the ideal conditions for brewing as they only operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bar.
In recent years, espresso machines powered by compressed air-pump are becoming increasingly popular. They use an air-compressor to push hot water across the ground, and are more mobile than electric steam-driven espresso machine sale machines.