Sour milk is a substitute for buttermilk in baked goods. Sour milk is also used as a starter ingredient for yogurt and cheese making, so knowing how to make sour milk at home is useful. Either vinegar or lemon juice mixed with milk will sour it.
Measure 1 cup milk into the pitcher.
Add 1 tbsp. of lemon juice or vinegar to the milk.
Stir with fork for 30 seconds.
Set the timer for five minutes. Use the sour milk when the timer goes off.