01 - Pour the milk into a saucepan and warm gently over medium heat, stirring occasionally, until it reaches 185°F (85°C). 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 (43–45°C). 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, whisking until smooth and fully incorporated.
04 - Pour the thinned starter mixture back into the saucepan with the remaining cooled milk. Stir thoroughly to ensure even distribution of the active cultures.
05 - Divide the mixture among clean jars or a single clean container. Cover loosely with lids or a breathable cloth.
06 - Place the containers in a warm, undisturbed spot—such as a turned-off oven with the interior light on or a dedicated yogurt maker. Incubate for 8 to 12 hours, checking after 8 hours for desired consistency and tanginess. Longer incubation produces a thicker, tarter yogurt.
07 - Transfer the set yogurt to the refrigerator and chill for at least 2 hours before serving. Store refrigerated for up to 1 week.