5 Killer Quora Answers On Machine Espresso

How Does Machine Espresso Work?

Machine espresso makes use of precise pressure and incredible filter technology to produce the coffee we love. How does it work exactly?

In order to make espresso hot water is pushed under pressure through finely ground coffee. The process is similar to that of making drip coffee. However the pressure is the main difference.

The Group Head

The group head is the portafilter that you place in the espresso maker when making it. It distributes water into the portafilter, and then regulates the pressure of the extraction. There are many different types of group heads each with distinct advantages and drawbacks. Some are designed to provide temperature stability while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some include a combination like the E61. This is a favorite among baristas since it provides multiple advantages in a single package.

As you can see in the photo above, the group head has numerous notches that you can place your portafilter before twisting it manually to secure it. A gasket of rubber is situated inside the notches to help create a seal while you insert your portafilter. The notches permit the precise placement of the portafilter. This is vital for an even extraction.

The group head not only lets the portafilter to be inserted easily, but it also maintains an even temperature. This is done by cycling hot water around the portafilter, and through the brew-basket, ensuring that the temperature is constant for extraction. It is important to note that even a small deviation can make the difference between a good and excellent espresso.

The Pump

The motorized pumps in rotary espresso machines provide the nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines which use levers. The pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger prior being pumped through the ground coffee in the group head.

Pumps tend to be cheaper than piston-driven machines, and they tend to last longer. However, both types of machines could be damaged by excessive use and inadequate cleaning. They also add mechanical complexity which can result in a high price tag on even the most basic models.

Some espresso machines employ steam pressure instead of a pump for brewing retro espresso maker. This can result in over-extraction because the boiler that makes steam also heats the water to boil. In addition these machines typically have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines make use of a rotary or vibration pump. A vibration model uses the vibrating disk to create pressure, while a rotating model pushes hot water through the ground at a fast speed. Both machines produce great espresso, but rotary machines are quieter, more durable and less likely to fail.

The Boiler

The boiler is the one that 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 a container for espresso grounds. The steam is then channeled into the cup. During this process, steam creates pressure that pushes through the grounds of the coffee. This creates a crema on the top of the espresso. This is the hallmark of a great espresso.

There are three different types of espresso machines, each having distinct pumps and brew temperature. There are various ways to control the brew as well as the size of cup that can be made by the machine.

The first pro espresso machine machines were steam types. They utilized a single boiler to make both steam and brew, but the pressure they could produce was not very high - two bars of atmospheric pressure at most. The coffee tasted bitter and burned. The modern espresso machine was designed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most popular espresso maker is a semi-automatic one that has an electric pump. This is what people envision when they think of an espresso machine. With a semi-automatic machine, you grind the beans and tamp them by hand. The pump controls the flow of water and pressure. This is a great solution that combines human control with mechanized reliability.

The Filter

Typically, espresso machines espresso machines have filters to separate the grounds of coffee as they move through the hot water. The filter is also a vital component of the machine's temp control, as it helps prevent overheating.

Filters also aid in flavor, as it permits a longer flowering period. This lets the beans release their flavors, and allows for a better extraction.

However, it is important to keep in mind that even a top filter can produce a bad cup of coffee, since the quality of the beans and extraction are important.

It's in this area that the magic occurs. This is what makes espresso taste so good. The grouphead, also called the brewhead, is where the portafilter (the thing you put the ground coffee in) is placed when you're making espresso.

Steam-driven espresso machines make use of hot water that is heated inside an airtight vessel to create steam. The steam then pushes hot water through grounds of coffee under high pressure. These machines are less expensive and easier to maintain than pumps-driven models. However, they are limited in their ability to produce the perfect conditions for brewing, as they only operate at 1-1.5 bars of pressure. While the perfect shot requires 9-10 bars.

In recent years, compressed air pump-driven espresso machines have been gaining popularity. They utilize an air compressor to force hot water into the grounds and are significantly more portable than steam-driven electric machines.