What ingredient is added to a Sour cocktail to provide sweetness?

In a Sour cocktail, the essential characteristic is the balance between acidity and sweetness. The ingredient that is commonly added to achieve this sweetness is simple syrup or sugar. Simple syrup is a mixture of sugar and water, often used in cocktails for its ease of mixing and ability to dissolve easily. It enhances the overall flavor profile of the cocktail by counteracting the tartness from the sour ingredient, typically citrus juice.

Using simple syrup allows bartenders to create a harmonious blend that appeals to the palate, ensuring that the drink is not overly sour. While honey can also be a sweetening agent, it introduces its own distinct flavor and may not blend as seamlessly as simple syrup. Soda water is primarily used to add fizz and does not contribute to sweetness. Fruit juice, although it can add sweetness, primarily serves as the sour component in Sour cocktails, such as lemon or lime juice. Therefore, the addition of simple syrup or sugar is the most straightforward and effective way to achieve the desired sweetness in these beverages.