Pour the milk into the Instant Pot, close the lid and press the Yogurt button until it says BOIL.
Take the lid off and cover the boiled milk with a tea towel. Allow it to cool to at least 115°F.
Add the yogurt or starter culture to the milk and mix well. Close the lid and set the Instant Pot to 8 - 24 hours using the Yogurt button.
Transfer your Greek yogurt to a large mason jar or glass container to refrigerate up to 2 weeks.
Optional - If you prefer extra thick yogurt, strain it over a bowl and collect the whey.