13 Things About Machine Espresso You May Not Have Considered
13 Things About Machine Espresso You May Not Have Considered
Blog Article
How Does Machine Espresso Work?
The machine espresso is made using precision pressure, and a filtering system that is awe-inspiring to create the coffee you 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. However, the pressure is the primary difference.
The Group Head
As the name implies, the group head is where you place your portafilter while making espresso. It disperses water in the portafilter and regulates the pressure of extraction. There are a variety of types of group heads, each with their distinct advantages and disadvantages. Some are specifically designed for temperature stability while others are specifically designed to handle pre-infusion. Some are designed to control the lever. Some are a combination, like the E61. This is a popular choice among baristas due to the fact that it has multiple advantages in a single package.
As you can see in the photo above the head of the group is fitted with several notches. The portafilter is placed inside these notches, and then turn the head around to secure it. A gasket made of rubber is placed within the notches to create a seal as you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is vital to ensure an efficient extraction.
Aside from allowing you to easily insert your portafilter, the group head is also responsible to maintain an even temperature. This is done by cycling hot water around the portafilter and through the brew-basket, making sure that the temperature is at the right level for extraction. This is vital, because even a small difference in temperature can make the difference between good and great espresso.
The Pump
The motorized pumps used in espresso machines rotary provide nine atmospheric bar pressure that is required for espresso extraction. This differs from manual piston machines that use levers. The pressure is built by pumping water through a heat-exchanger and then through the ground coffee.
Pumps tend to be less expensive than piston-driven machines, and they tend to last longer, but both types of machines can get damaged through overuse and lack of cleaning. Pumps are also more complicated mechanically, and can add to the cost of even the simple models.
Some espresso machines make use of steam pressure instead of a pump for brewing espresso. The drawback of this is that the same boiler that produces steam also increases the temperature of the water until it reaches boiling, which can lead to excessive extraction. These machines also have to constantly rebuild their pressure between cups. This requires energy and time.
A majority of espresso machines use either a rotary or vibration pump, with a vibration model using a vibrating disc to create the pressure and the rotary model pushing hot water through the grounds under high speed. Both machines can make great espresso, but rotary machines are quieter, more durable and less likely to break down.
The Boiler
The boiler is what is used to heat the water to the perfect temperature to extract. The steam that is created is then directed to the portafilter, which is the container that holds the espresso coffee grounds. It is then funneled into the cup. During this process, the steam creates pressure to push through the coffee grounds. This results in a crema on the top of the espresso. This is a hallmark of a great espresso.
There are three types of espresso machines, each with different pumps and brew temperature. There are a variety of ways in which the brew could be controlled as well as the size of the cup the machine can produce.
The first espresso machines were steam types. The first espresso machines coffee espresso machine were steam types. The coffee tasted bitter and burned. The modern espresso machine was created by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.
The most common espresso machine is a semiautomatic one with an electric pump. When people think of espresso machines, they imagine 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 perfect compromise between human control and mechanised reliability.
The Filter
Espresso machines usually use filters that separate the grounds of the coffee from hot water. The filter is also an essential component of the temperature control system, as it keeps the machine from overheating.
It also improves flavor, as a filter can allow for a longer bloom phase. This allows the beans to release their flavors and provides an opportunity for a better extraction.
It is important to keep in mind that even the finest filter can make a bad cup of coffee. The quality of the beans, and the extraction process remain crucial.
It's here that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead (also known as the brewhead) is where you place the portafilter, the thingy that you use to put the grounds of coffee into when making espresso.
Steam-driven espresso machines use hot water heated in an airtight vessel to create steam. The steam then pushes hot water through grounds of coffee at high pressure. These machines are cheaper and easier to maintain than pumps-driven models. They are however limited to create the perfect brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.
In recent years, compressed air-driven espresso machines have been gaining popularity. They make use of an air compressor to force hot water through the ground and are much more mobile than electric steam-driven espresso machines.