Ensure that the pressure cooker’s inner pot is absolutely clean. Add 2 cups of the milk to the inner pot. Add the yogurt, whisk very well until incorporated. Pour in the rest of the milk, and whisk again.
Cover and select YOGURT on Med. Set the timer to 8 hours or up to 12 hours for tangier yogurt; press and hold START.
Once the timer is up, press CANCEL. Remove inner pot, cover with foil, and refrigerate for at least 4 hours. Remove to separate containers; you can also freeze in small batches, and be sure to save two tablespoons of this yogurt so that you have the starter to make your next batch.