Clean and dry the Instant Pot liner and all utensils
Add milk to the Instant Pot. Put the lid on, but do not Seal. A glass lid can be used instead if you have one that fits. Press the Yogurt button until BOIL is displayed.
The Instant Pot will beep and display YOGT when the cycle is complete. Check to make sure that the milk is 180-200F.
Cool milk to 105-115F, either by cooling at room temp for an hour, or in an ice bath for 5-10 minutes.
Put the yogurt starter into a glass measuring cup, and add 1 cup of the cooled milk. Whisk well to thoroughly combine. Add the starter mixture back to the pot, and mix to make sure the starter is fully incorporated.
Put the lid back on the pot, and select the Yogurt function again. The timer will count up to 8 hours. If you prefer your yogurt more tangy, increase the time.
When the incubation is complete, the Instant Pot will display YOGT. The yogurt should have thickened. Cover the yogurt and put in the refrigerator to chill for a few hours to stop the incubation process and thicken slightly.
Save 2 tbsp to use as starter for your next batch. Add sweeteners or flavourings if desired. Refrigerate the yogurt up to 2 weeks.