9 . What Your Parents Taught You About Machine Espresso

How Does Machine Espresso Work?

Machine best budget espresso machine employs precise pressure and mind-blowing filter technology to create the perfect cup of coffee. How exactly does 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 Head of the Group

As the name suggests, the group head is the place you put your portafilter in when making espresso. It disperses water in the portafilter, and regulates the pressure during the extraction. There are many different types of group heads each with their own advantages and disadvantages. Some are focused on temperature stability, while others on pre-infusion capabilities, and still others are designed to control the lever. Some come with a combination of both, such as the E61. This is a very popular choice for baristas as it provides a variety of benefits in one package.

As you can see in the photo above, the group head has several notches to put your portafilter, then twist it with your hands to secure it. A gasket of rubber is situated in the notches to create a seal while you insert your portafilter. The notches permit precise placement of your portafilter. This is essential for a consistent 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 basin, ensuring that the temperature is constant for extraction. It is important to remember that even a few degree variation can mean the difference between a good and excellent espresso.

The Pump

Motorized pumps in espresso machines rotary provide nine atmospheric bar pressure required for espresso extraction. This is different from manual piston machines that use a lever. The pressure builds by drawing tap water from a reservoir, and pumping it through a heat exchanger before being pushed through the ground coffee inside the group head.

Pumps tend to be less expensive and last longer than piston-driven machines. However, both kinds of machines may degrade due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase prices of even simpler models.

Some espresso machines make use of steam pressure instead of a pump for brewing espresso. The downside is that the same boiler that produces steam also increases the temperature of water to boiling, which can lead to over-extraction. Additionally these machines typically have to rebuild their pressure between cups, which requires time and energy.

Many espresso machines utilize an rotary or vibrating pump, which has a vibration model using a vibrating disc to create pressure, and a rotary model pushing hot water through the grounds at high speed. Both models are capable of producing excellent espresso, but the rotary pumps are quieter, and more durable than vibration pumps.

The Boiler

The boiler will heat the water to the ideal temperature to extract. The resultant steam then reaches the portafilter which holds the ground espresso coffee, and gets funnelled down into the cup. During this process, the steam causes pressure to push through the coffee grounds. This results in a crema on top of the espresso. This is a sign of a great espresso.

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

The earliest espresso machines were steam type. They used one boiler to make both brew and steam, but the pressure they could produce was not very high - two bars of atmospheric pressure maximum. This resulted in the coffee tasting burnt and bitter. The modern espresso machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most common espresso machine is a semiautomatic model with an electric pump. These are what people imagine when they think of an espresso coffee machine for home maker. With a semi-automatic machine, you grind the beans and then tamp them yourself but the pump is able to regulate the flow of water and pressure. This is a fantastic compromise between human control and 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 crucial component of the temperature control system, because it stops the machine from overheating.

It also aids in flavor, as a filter can allow for a longer bloom phase. This lets the beans release their flavor and allows for better extraction.

However it is crucial to keep in mind that even a top filter can make a terrible cup of coffee, since the quality of the beans and extraction are vital.

It's here that the magic happens. This is the reason why espresso tastes so delicious. The grouphead (also called the brewhead) is where you put the portafilter, the thingy that you put the grounds of your coffee into when making espresso.

In the steam-driven espresso machines uk machine hot water is heated in an airtight tank to create steam. This then pushes the hot water through the grounds at high pressure. They are less expensive and easier for the owner to maintain than pumps-driven models. They are however limited in their ability to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The ideal 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 through the grounds and are much more portable than electric steam-driven machines.