In an Instant Pot with a yogurt function, remove the seal from the lid. Clean the lid and the inner pot with hot soapy water, or place in the dishwasher, and dry thoroughly. Set aside. (see note)
Heat milk in clean medium pot over medium heat until it has started to steam and bubble around the edges, to 180ºF (we like to use our Thermapen for this).
Place the hot milk in the Instant Pot inner liner, and let cool until it reaches 105ºF - 110ºF, about 40 minutes.
Once it has cooled enough, in a small bowl add the live culture together with about ¼ cup of the milk and whisk until it is fully combined. Add it back to the inner pot, whisk until combined.
Press the Yogurt function on the Instant Pot until it displays a timer. Set for 8-16 hours, depending on how tangy you want your yogurt and close the lid (without the inner seal). It does not matter whether you press sealing or not.
Once finished, smell the yogurt. It should be pleasantly tangy.
To make greek yogurt: Line a fine mesh strainer with either a clean cotton kitchen towel, a coffee filter and two layers of cheesecloth. Pour the finished yogurt inside and let it drain for 2-6 hours, or until desired consistency.
Yogurt will keep in the refrigerator for 5-7 days.