What is the function of a cocktail shaker?

The function of a cocktail shaker is primarily to chill the drink and mix the ingredients effectively. When shaking ingredients together, the ice inside the shaker cools the drink rapidly, which is crucial for cocktails that benefit from being served cold. Additionally, shaking an infusion of spirits, mixers, and other components ensures that they combine thoroughly, allowing for a well-mixed drink. This technique not only enhances the flavor profile of the cocktail but also creates a pleasant texture.

The other options highlight processes related to cocktail preparation but do not encapsulate the purpose of a shaker as effectively. Measuring ingredients accurately is typically done with jiggers, while straining the cocktail before serving is generally performed with a separate strainer after shaking. Serving the drink directly might involve using the shaker, but that is not its primary function. The main aim of a shaker is to combine and chill, making option A the best choice.