Thick Strained Whole Milk Greek Yogurt

Steps

1. Wash a heavy pot, whisk, thermometer, a lidded glass jar or bowl, a fine-mesh strainer and a cheesecloth or coffee filter in hot soapy water, then rinse with very hot water and let air-dry on a clean rack.
2. Take the yogurt-plain starter out of the fridge so it warms slightly while the milk heats.
3. Pour the whole milk into the pot and heat over medium-low, stirring often so it doesn't scorch, until it reaches 180°F (82°C), about 15 to 20 minutes.
4. Hold the whole milk at 180–185°F (82–85°C) for 10 to 20 minutes, lowering the heat and stirring gently; this firms up the final texture.
5. Take the pot off the heat and let the milk cool, stirring now and then, until it reads 108–112°F (42–44°C), about 30 to 45 minutes; setting the pot in a sink of cool water speeds this up.
6. In a small clean bowl, whisk the yogurt-plain starter with a ladle of the warm milk until smooth, then stir this mixture back into the pot of milk.
7. Pour the cultured milk into the clean jar or bowl, cover, and incubate at 108–112°F (42–44°C) for 6 to 8 hours, undisturbed, in an oven with only the light on or a yogurt maker, until set like soft custard and tangy.
8. As soon as it sets, refrigerate the yogurt at 40°F (4°C) or below until cold, about 2 hours.
9. Line the strainer with cheesecloth or a coffee filter, set it over a deep bowl, spoon in the chilled yogurt, cover, and strain in the refrigerator for 6 to 8 hours or overnight.
10. Stir the strained yogurt until creamy, divide into 4 portions, and keep covered in the fridge for up to 1 week; save 45 g as the starter for your next batch.