Heat the milk in a pot over medium heat. Stir frequently until the milk reaches 180°F - 200°F / 82 °C - 93°C.
8 Cups Whole Milk
Remove the milk from the heat and transfer it to an ice bath, let it cool to 100 - 110°F / 37 - 43°C.
Temper the yogurt by gradually adding 1 cup of milk, stirring constantly. Once the yogurt is smooth, mix with the remaining milk and stir until combined.
1 Cup Plain Yogurt
Transfer the milk to a jar and wrap it with a tea towel, this will help to keep the milk warm. Let it sit in a warm place (100 - 110°F / 37 - 43°C) for 4 to 8 hours, or until it has thickened. I leave mine inside the oven turned off with the light on for 4 hours.
Line a strainer with cheesecloth and place it over a bowl. Allow the yogurt to strain in the fridge for at least 3 hours or until it reaches the desired consistency. I usually leave it overnight. After straining yogurt, you will get a byproduct called whey. Whey is an excellent addition to bread recipes, adding protein and flavor.
Enjoy!