What is a key component of an espresso machine?

A pressure gauge is a key component of an espresso machine because it provides essential information about the pressure being applied during the extraction process. Proper pressure is crucial for brewing espresso, as it helps to ensure that water is forced through the coffee grounds at the optimal rate, resulting in a well-extracted shot. The standard brewing pressure for espresso is typically around 9 bars. Monitoring this pressure allows baristas to make necessary adjustments to achieve the desired flavor profile and extraction quality.

While elements like a grind adjustment scale, cleaning brushes, and moisture control are all important in the broader context of espresso preparation and machine maintenance, they serve different purposes. The grind adjustment scale affects the coarseness of the coffee grounds, which influences the flavor but does not measure extraction pressure directly. Cleaning brushes are essential for maintaining the equipment, ensuring hygiene and efficiency, but do not directly relate to the brewing process. Moisture control, while important in coffee storage and brewing, is not a component of the espresso machine itself. Thus, the pressure gauge stands out as a critical feature for ensuring the right conditions for espresso extraction.