Sour mix is a sweet and tangy cocktail ingredient commonly used in drinks like margaritas and whiskey sours. It typically consists of a blend of lemon juice, lime juice, and simple syrup, which is made from sugar and water. This mix adds a refreshing flavor and balances the sweetness of other ingredients in cocktails. Bartenders often prepare sour mix in large batches for convenience, allowing for quick drink preparation. While many bars use commercial sour mix, homemade versions can be made easily by combining fresh citrus juices with sugar. This ensures a fresher taste and can be adjusted to personal preference.