1. Old yogurt on the market, and boxed pure milk.

2. Wash the inner container of yogurt machine and blanch it with boiling water for disinfection.

3. Pour the boxed pure milk into the pot and heat it to about 40 degrees.

4. Pour the heated pure milk into the scalded container.

5. Mix 3-4 spoonfuls of old yogurt into pure milk and mix well.

6. Cover it, put it in a yogurt machine, and heat it for 8- 10 hour. The surface is smooth and caked, and it has a strong flavor of yogurt. The eating effect is the best after refrigeration.

7. Self-made old yogurt is not sweet. You can eat it after adding sugar or honey. I added pineapple and red raisins here, which tastes great.