Make 2 liters of yogurt.
Heat the milk over a very low flame until it reaches 93°C (200ºF).
As the milk heats up, stir it occasionally.
It usually takes about 20 to 25 minutes for the milk to reach 93ºC (200ºF).
Cool the milk down to 45°C(114ºF); keep the pot partially covered and stir occasionally.
Once the milk has cooled down to 45°C (114ºF), mix 200 mL of the milk with 1 cup of yogurt.