Refrigerated homemade yogurt will last for you to 2 weeks. It tastes best in the first 4 to 5 days. However, as the active culture ages, it starts to develop a sour taste. It is still edible, delicious, and perfect for yogurt drinks, curries, and baked goods. Of course, you can use it to make more yogurt. Of course, yogurt is a great substitute for sour cream and perfect for making chocolate cakes.