What does it mean to reduce a sauce?

Reducing a sauce involves simmering it to evaporate some of its water content, which concentrates the flavors and increases thickness. This technique is often used to enhance the taste of the sauce, making it richer and more intense, as well as improve its texture. By simmering, the water component evaporates, leaving behind a sauce that has a more robust flavor profile and desired viscosity.

The other options do not accurately represent the process of reducing a sauce. Increasing the flavor intensity is a primary goal of reduction, and adding more liquid or cooling the sauce would not achieve that aim. Instead, those actions would dilute the flavors or alter the sauce's temperature without concentrating it. Thus, the correct interpretation of reducing a sauce is focused on thickening and intensifying its flavor through simmering.