A Relevant Rant About Machine Espresso
A Relevant Rant About Machine Espresso
Blog Article
How Does Machine Espresso Work?
Machine espresso uses precision pressure and amazing filter technology to make the coffee we love. What exactly does it work?
Espresso is made by forcing hot water under high pressure through finely-ground coffee. The process is similar to 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 disperses water into the portafilter, and regulates the pressure during the extraction. There are various kinds of group heads, each with their unique advantages and drawbacks. Some focus on temperature stability, others on pre-infusion capabilities, while others are designed to control the lever. There are some that have a combination of features, such as the E61, which is considered the classic choice among many baristas because of its ability to provide multiple benefits in one package.
As you can see in the picture above the group head is equipped with several notches. It is possible to place your portafilter into these notches and turn the head around to secure it. A gasket made of rubber is positioned in the notches to create a seal when you insert your portafilter. The notches on the head permit a precise positioning of the portafilter which is necessary to ensure an efficient extraction.
In addition to allowing you to easily place your portafilter in, the group head is responsible for maintaining an even temperature. It does this by cycling hot water through the brew basket and around the portafilter to ensure that it's always at the right temperature to extract. It is important to remember that even a tiny differences can make the distinction between a good and great espresso.
The Pump
In contrast to piston machines that are manually operated, which rely on a lever to pressurize water, the rotary espresso machines use motorized pumps to supply the nine atmospheric bars of pressure needed for espresso extraction. The pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger prior being pushed through the ground coffee in the group head.
Pumps are generally less expensive than piston-driven machines and tend to last longer, but both types of machines can become damaged due to excessive use and poor cleaning. Pumps are also more complicated mechanically, and can add to the cost of even the most basic models.
Some espresso machines employ steam pressure instead of a pump in order to brew espresso. The drawback is that the boiler that produces steam also increases the temperature of the water to boiling which can cause excessive extraction. The machines must also continuously rebuild their pressure between cups. This requires energy and time.
A majority of espresso machines use a vibration or rotary pump, with a vibrating model using a rotating disc that generates the pressure, and a rotary model pushing hot water through the grounds under high speed. Both types of machines are capable of producing excellent espresso, however the rotary pumps are quieter, and more durable than vibration pumps.
The Boiler
The boiler makes the water warm to a temperature that is ideal to extract. The steam created will eventually reach the portafilter, which is the container that holds the espresso coffee grounds. It is then funneled into the cup. The steam creates enough pressure to push the grounds of coffee through. This creates a foam on top of the espresso. This is one of the hallmarks of a good espresso.
There are three kinds of espresso makers. They differ in the type of pump they use and how hot the coffee is. There are different ways that the brew can be controlled, as well as the dimensions of the cup the machine is capable of making.
The earliest espresso machines were steam type. The first espresso machines were steam-type machines. The coffee tasted bitter and burnt. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.
The most commonly used espresso machine is a semiautomatic model with an electric pump. These are the things people think of when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp the beans on your own while the pump controls the water flow and pressure. This is an excellent combination of human control and mechanized reliability.
The Filter
Espresso machines usually use a filter that separates the grounds of coffee from hot water. The filter is also an essential part of the machine's temperature control, as it helps prevent overheating.
A filter can also help with flavor because it allows for a longer flowering phase. This allows the beans to let their nuances out and provides the chance for better extraction.
It is important to remember 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 in this area that the magic happens. This is the reason why espresso tastes so delicious. The grouphead, also referred to as the brew head, is where the portafilter (the device you put the ground coffee in) is placed 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. This then pushes the hot water through the grounds with high pressure. They are less expensive and easier for the user to maintain coffeee than pumps-driven models. However, they are limited in their capacity to create the ideal brewing conditions, because they 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 force hot water through the ground, and are more mobile than steam-driven electric espresso machines.