What tool is used to measure the extraction time of espresso?

The use of a stopwatch or timer to measure the extraction time of espresso is essential in the coffee brewing process. Espresso requires a precise and controlled extraction time, typically between 25 to 30 seconds, to achieve the desired flavor and balance. Measuring this time accurately allows baristas to ensure that the coffee grounds are neither under-extracted (which would result in sour flavors) nor over-extracted (which would lead to bitterness).

In this context, a stopwatch or timer is the most appropriate tool as it provides an exact measurement, helping baristas to maintain consistency in their espresso shots. This level of precision is critical in a professional coffee-making environment where the quality of the espresso can significantly influence customer satisfaction.

While other tools such as a ruler, thermometer, or pressure gauge have their own roles in coffee preparation—like measuring grind size, monitoring water temperature, or assessing brewing pressure—they do not have a direct function in tracking the duration of the espresso extraction. Hence, they are not suitable for this specific purpose.