Ice is a fundamental ingredient in the world of cocktails. Primarily used to chill drinks, it also plays a crucial role in diluting the beverage to balance flavors. Ice can be used in various forms, such as cubes, crushed, or shaved, each bringing a different texture and cooling rate to the cocktail. Its presence is essential in classic cocktails like the Old Fashioned and Margarita, where it not only cools the drink but also slightly dilutes it, allowing the flavors to meld together harmoniously.