How To Resolve Issues With Machine Espresso
How To Resolve Issues With Machine Espresso
Blog Article
How Does Machine Espresso Work?
Machine espresso uses precision pressure and amazing filter technology to make the delicious coffee we enjoy. What exactly is it that makes it work?
In order to make espresso, hot water is forced under high 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
As the name suggests, the group head is the place you insert your portafilter when making espresso. It is responsible for dispersing water into the portafilter, and controlling the pressure that results from the extraction. There are a variety of types of group heads, each with their own advantages and disadvantages. Some are designed for stability in temperature, while others are designed to handle pre-infusion. Others are made to control the lever. Some come with a combination of both, such as the E61. This is a popular choice among baristas because it offers multiple benefits in a single package.
As you can see in the above photo the head of the group has a number of notches. You place your portafilter inside these notches, and then twist the head to lock it. There is also a rubber gasket that is a part of the notches to help create a seal when you insert your portafilter into the machine. The notches permit the precise placement of the portafilter. This is crucial to ensure an accurate extraction.
Apart from allowing you easily place your portafilter in, the group head is responsible to maintain an even temperature. This is done by cycling hot water around the portafilter and through the brew-basket, ensuring the temperature is always right for extraction. It is important to note that even a small deviation can make the difference between a decent and a excellent espresso.
The Pump
Motorized pumps in rotary espresso machines supply the nine atmospheric bar pressure that is required for espresso extraction. This is different from manual piston machines which use levers. This pressure builds up by drawing tap water from a reservoir and pumping it through a heat exchanger prior to being pushed through the ground coffee in the group head.
Pumps are typically less expensive than piston-driven machines and tend to last longer. However, both types of machines could get damaged through overuse and lack of cleaning. They also increase the complexity of mechanical systems which can result in an expensive price for even the most basic models.
Some espresso machines do away with the pump completely and utilize steam pressure to make espresso. This could lead to over-extraction since the boiler that makes steam also heats the water until it comes to a boil. Additionally the machines often have to restore their pressure between cups, which takes time and energy.
Many espresso machines make use of an rotary or vibrating pump, with a vibration model using a vibrating disc to create pressure, and rotating models that push hot water through the grounds under high speed. Both machines can make great espresso however rotary machines tend to be more quiet, durable and less likely to break.
The Boiler
The boiler makes the water warm to a temperature that is ideal to extract. The steam that is produced reaches the portafilter that contains the ground espresso and is then pumped into the cup. During this process the steam creates enough pressure to push the grounds of coffee through. This creates a foam on the 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 brew temperature. There are also different ways in which the brew could be controlled, as well as the size of the cup that the machine can make.
The first espresso machines were steam-type. They employed a single boiler to make both steam and brew, but the pressure they could produce was not very high - two bars of atmospheric pressure maximum. This led to the coffee tasting burnt and bitter. The modern espresso machine was designed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.
The most well-known espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they imagine these machines. With a semi-automatic espresso machine, you grind the beans and then tamp them by hand. However, the pump provides regulated water flow and pressure. This is a great compromise between the human touch and the mechanized accuracy.
The Filter
Espresso machines typically use a filter that separates the grounds of the coffee from hot water. The filter is also a vital component of the machine's temp control, as it helps prevent overheating.
It also aids in flavor, as a filter can allow for a longer bloom phase. This allows the beans to release their flavors and provides the chance for better extraction.
However it is crucial to remember that even a top filter can make a terrible cup of coffee, as the quality of the beans and extraction is still essential.
It's here that the magic happens. This small espresso machine is what makes espresso taste so delicious. The grouphead (also called the brewhead) is where you place the portafilter, the device that you use to put the grounds of your coffee into while making espresso.
Steam-driven espresso machines make use of hot water that is heated in an airtight container to create steam. The steam then moves hot water through the grounds of the coffee under pressure. These types of machines are usually less expensive and simpler to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-pump-driven espresso machines have been gaining popularity. They use an air compressor to force hot water into the grounds and are more portable than steam-driven electric machines.