Substitutes for sour milk in a recipe may include 2 percent milk and lemon juice, yogurt or tofu. These substitutions are usually healthier options than sour milk or buttermilk.
To use 2 percent milk and lemon juice in place of sour milk, measure out the amount of milk indicated in the recipe. Thoroughly stir in the lemon juice before adding the mixture to the recipe. If using yogurt, stir 1 tablespoon of milk into the correct amount of yogurt. Gradually add more milk to achieve the desired thickness. To substitute with tofu, choose the softest tofu available, and mix it with 1 tablespoon of water or more to achieve the appropriate consistency.