How Does Machine Espresso Work?

The machine espresso is made using precise pressure, as well as a filter technology that is mind-blowing to create the coffee you love. How does it work exactly?

To make espresso, hot water is pushed under pressure through finely ground coffee. The process is similar to making drip coffee. However, the pressure is the primary difference.

The Group Head

The group head is the portafilter is inserted when you are making espresso. It disperses water into the portafilter, and then regulates the pressure of extraction. There are a variety of group heads each with 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 favorite among baristas since it provides multiple benefits in a single package.

As you can see in the photo above The group head features several notches to place your portafilter before twisting it manually to lock it in. A rubber gasket is located inside the notches, which helps create a seal as you insert your portafilter. The notches on the head allow for an exact placement of the portafilter, which is crucial to ensure a consistent extraction.

The group head does not just allow the portafilter to be inserted easily but also maintains an even temperature. This is done by cycling hot water around the portafilter and through the brew-basket, ensuring the temperature is always right to extract the coffee. It is important to realize that even a small variation can mean the difference between a decent and a great espresso.

The Pump

In contrast to manual piston machines which rely on a lever to pressurize water, Rotary espresso machines rely on motorized pumps to deliver the nine atmospheric bars of pressure that are required to extract espresso. The pressure builds up by removing tap water from a reservoir and Espresso makers pumping it through a heat exchanger prior to being pumped through the ground coffee in the group head.

Pumps are generally less expensive than piston-driven machines and tend to last longer, although both types of machine can become damaged due to excessive use and poor cleaning. Pumps are also more complex mechanically, which can increase the price of even the simpler models.

Some espresso machines employ steam pressure instead of a pump in order to brew espresso. The downside is that the boiler that produces steam also increases the temperature of the water until it reaches boiling which could lead to excessive extraction. These machines also have to constantly rebuild their pressure in between cups. This takes energy and time.

Many espresso machines employ a vibration or rotary pump, with a vibrating model using a vibrating disc to create pressure, and a rotary model pushing hot water through the grounds at high speed. Both machines can produce excellent espresso but rotary machines are more quiet, durable and less likely to break down.

The Boiler

The boiler is what makes the water warm to the right temperature to extract. The resulting steam reaches the portafilter which holds the ground espresso coffee, and is then pumped down into the cup. During this process the steam is able to create enough pressure to push the grounds of the 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 types of espresso makers, which differ in the type of pump they use and the degree of heat that the brew is. There are many ways to control the amount of brew, as well as the size of cup that can be produced by the machine.

The first espresso machines were steam-type. The earliest espresso machines were steam-type machines. The coffee tasted bitter and burned. The modern best budget espresso machine machine was developed by the Milanese producers Luigi Bezzerra & Desiderio Pavoni.

The most well-known espresso maker is a semi-automatic one that has an electric pump. This is what people envision when they imagine an espresso machine. Semi-automatic machines require you to grind and tamp your beans yourself however the pump controls the flow of water and pressure. This is a great compromise between the human touch and the mechanised accuracy.

The Filter

Espresso machines usually have filters that separate the grounds of coffee from hot water. The filter is also an essential component of the machine's temp control, as it prevents overheating.