Clean the inner pot, lid, and silicone ring. Run a steam cycle with 1 cup water and vinegar. Let cool and dry completely.
Add milk to Instant Pot. Use the 'Yogurt' button or 'Sauté' function to bring milk to 180–190°F. Stir to avoid hot spots.
Cool milk to 105–115°F by letting it rest or using a cold water bath. Remove any skin on the surface.
Mix 2–3 tablespoons of plain yogurt with a bit of cooled milk. Whisk smooth, then stir into the pot.
Press 'Yogurt' and set 8–10 hours. For manual method, wrap pot in towels and leave in a warm oven with the light on for 8–12 hours.
After incubation, transfer the pot to the fridge for at least 4 hours to firm up the yogurt.
For Greek yogurt, strain through cheesecloth or nut milk bag for 2–12 hours.
