01 - Pour the milk into a saucepan and warm gently over medium heat, stirring occasionally, until it reaches 185°F. Do not allow the milk to come to a boil.
02 - Remove the saucepan from heat and let the milk cool to between 110°F and 113°F. Use a kitchen thermometer to monitor the temperature accurately.
03 - In a small bowl, combine the yogurt starter with a few tablespoons of the cooled milk. Whisk until completely smooth and free of lumps.
04 - Pour the thinned starter mixture back into the saucepan with the remaining cooled milk. Stir thoroughly to ensure even distribution of the live cultures.
05 - Pour the inoculated milk into a clean container or divide among individual jars. Cover loosely with lids or a clean towel.
06 - Place the containers in a warm, draft-free spot for 8 to 12 hours. A turned-off oven with the interior light on, a yogurt maker, or a warm cooler all work well. The longer the incubation, the tangier and firmer the yogurt will become.
07 - Once the yogurt has reached your preferred consistency and tanginess, transfer the containers to the refrigerator. Chill for at least 2 hours before serving to allow the yogurt to fully set.
08 - Keep the yogurt refrigerated. It will stay fresh for up to 1 week. Reserve a few tablespoons to use as the starter for your next batch.