Rhonda Mortimer asked 2 months ago
How Does Machine Espresso Work?
Machine espresso utilizes precise pressure and mind-blowing filter technology to create the coffee we love. What exactly is it that makes it work?
To make an espresso hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee but the difference is in the pressure.
The Group Head
As the name suggests, the group head is where you place your portafilter when brewing espresso. It disperses the water into the portafilter, and regulates the pressure of the extraction. There are various kinds of group heads each with its unique advantages and drawbacks. Some are specifically designed for the stability of temperature while some are designed to handle pre-infusion. Some are designed to control the lever. There are even some that include a mix of features, like the E61, which is the most popular choice among baristas for its ability to offer multiple benefits in one package.
As you can see from the image above, the group head is fitted with a variety of notches. It is possible to place your portafilter in these notches and then turn the head around to secure it. A gasket made of rubber is placed inside the notches to help create a seal as you insert your portafilter. The notches allow for precise placement of the portafilter. This is crucial for an efficient extraction.
In addition to allowing you easily insert your portafilter, the group head is also responsible for maintaining a consistent temperature. This is accomplished by cycling hot water around the portafilter and through the brew-basket to ensure that the temperature is constant to extract the coffee. It is important to realize that even a few degree variation can mean the difference between a good and excellent espresso.
The Pump
The motorized pumps in espresso machines that rotate provide the nine atmospheric bar pressure that is required to extract espresso. This is different from manual piston machines which use a lever. 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 due to overuse and insufficient cleaning. Pumps are also more complicated mechanically, and can add to the cost of even simplest models.
Certain espresso machines can eliminate the pump completely and use steam pressure to brew espresso. The drawback of this is that the same boiler that produces steam also raises the temperature of water to boiling, which can lead to excessive extraction. In addition these machines typically have to restore their pressure between cups, which takes time and energy.
Many espresso machines make use of a vibration or rotary pump, which is a vibration model that uses a vibrating disc to create the pressure and an rotary model that pushes hot water through the grounds at high speed. Both machines can produce excellent espresso but rotary machines are more quiet, durable and less likely to break down.
The Boiler
The boiler is the component that heats water to the optimal temperature to extract. The resulting steam reaches the portafilter that contains the ground espresso and gets funnelled down into the cup. During this process, the steam causes pressure to push through the coffee grounds. This creates a layer crema on top. This is one of the hallmarks of a great espresso.
There are three types of espresso makers, and they differ in the type of pump they use and how hot the espresso is. There are various ways in which the brew can be controlled as well as the size of the cup the machine can make.
The earliest espresso machines were steam types. They used one boiler to create steam and brew, but the pressure they could create was minimal – two bars of atmospheric pressure maximum. The coffee tasted bitter and burnt. This is the reason Milanese makers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most common espresso maker is a semi-automatic one that has an electric pump. When people think of espresso machines, they imagine these machines. Semi-automatic machines require you to grind and tamp the beans on your own, but the pump regulates the flow of water and pressure. This is a great solution that combines human control with mechanised consistency.
The Filter
Espresso machines typically use a filter that separates the grounds of the coffee from the hot water. The filter is also an essential part of the temperature control system because it stops the machine from overheating.
It also aids in flavor, since a filter can allow for a longer bloom phase. This allows the beans to release their flavors, and also allows for 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, are still crucial.
It’s here that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead, also referred to as the brew head, is where the portafilter (the container you place the coffee grounds into) is placed when making espresso.
In a steam-driven espresso machine hot water is heated in an airtight container to produce steam, which then pushes the hot water through the grounds at a high pressure. These machines are less expensive and easier for the user to maintain than pumps-driven models. However, they are limited in their capacity to create the perfect conditions for brewing, since they are only operating at 1-1.5 bars of pressure. The perfect shot requires 9-10 bars.
In recent times, professional espresso machine machines powered by compressed air-pump are becoming increasingly popular. They use an air compressor to force hot water into the ground. They are also more mobile than steam-driven electric Espresso Coffee Machine With Milk Frother machines.