What does it mean to agitate a liquid in cooking?

Agitating a liquid in cooking refers to the process of stirring, shaking, or otherwise disturbing it. This technique is often used to ensure even mixing of ingredients or to help incorporate air into the liquid, as seen in recipes that require emulsification or aeration. For example, when making a vinaigrette, agitating the mixture helps to combine oil and vinegar more effectively.

The other options do not capture the essence of agitation. Freezing a liquid quickly is a different process related to temperature changes rather than movement. Boiling it rapidly involves heat application but does not imply any stirring or movement. Letting it sit undisturbed is the opposite of agitation, as it involves no action on the liquid. Thus, the correct understanding of agitating a liquid emphasizes movement to achieve specific culinary outcomes.