To sterilize the Instant Pot, secure the lid, close the pressure-release valve, and select the high pressure function for 5 minutes. Once finished, manually release the pressure using an oven mitt or towel to protect your hand from the escaping steam. Pour out the water.
Add the whole milk into the Instant Pot inner pot. Use the yogurt function to boil the milk.
1 gallon whole milk
Remove the inner pot and let the milk cool to 110F or 43C using a thermometer. The exact temperature is crucial for the live cultures to thrive. You can speed up this process by creating a cold water bath in the kitchen sink.
Stir in the plain yogurt to the cooled milk.
4 tbsp plain yogurt
Pour the mixture back into the Instant Pot inner pot. Set the yogurt function for 8 hours. For a tangier yogurt, increase the incubation time.
Optional: I strain the finished yogurt via a cheesecloth-lined sieve to make Greek-style yogurt, saving the whey in a bowl below for other recipes.
Refrigerate the yogurt for at least 2 hours before serving.
Video
Notes
Instant Pot:For reference, I'm using the (affiliate link to follow) 3 Quarts (5.7l) Instant Pot Duo 7-in1 Multicooker in this recipe.Cleanliness: Ensure all equipment, including the Instant Pot inner pot and lid, is thoroughly sterilized to prevent contamination.Yogurt seal: Make sure to have two seals available for your Instant Pot as it easily absorbs the flavor of savory dishes which doesn't work for yogurt making. I have a dedicated seal for yogurt making.Temperature control: Achieving the correct temperature for cooling the milk is essential for successful yogurt making.