Pour milk into Instant Pot.
Lock the lid onto the Instant Pot and set Instant Pot to "yogurt - boil" setting.
After this cycle, use the thermometer to ensure that the milk has reached 180 F. This is important! If the milk is not yet 180 F, repeat the cycle again.
Remove the Instant Pot insert and set it aside to cool. Watch the temperature until it cools to 110 F. (You can carefully set the insert in a large bowl of ice water if you want to speed the cooling process up.)
A thin skim layer should appear on top of the milk. Remove and discard this layer.
Measure out 1 cup of this cooled milk and add it to a separate bowl with the yogurt.
Whisk the milk and yogurt together and then add the mixture back to the Instant Pot insert.
Whisk again to ensure that the milk and yogurt are well blended.
Lock the lid and press the "yogurt - normal" setting and set for 12 hours.
After the timer goes off, place the insert in the refrigerator, covered with a dish towel, for 4 hours to set.
Scoop yogurt into clean containers, for example canning jars.
Store in the refrigerator for up to 1 week.
Enjoy plain, with granola and/or fresh fruit!