Drinkable Whisked Whole Milk Yogurt

Steps

1. Wash a heavy pot, a whisk, a ladle, a thermometer and a 1.2-quart (1.2 L) jar in hot soapy water, rinse, then scald them with boiling water to sanitize. Set the Greek yogurt out so it warms slightly while the milk heats.
2. 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 15–20 minutes.
3. Hold the milk at 180–185°F (82–85°C) for 10 minutes, stirring now and then and lowering the heat as needed.
4. Take the pot off the heat and cool the milk to 108–112°F (42–44°C), about 30 minutes on the counter, or about 10 minutes with the pot set in a sink of cold water; stir and check often. Skim off any skin.
5. Ladle about one-quarter of the warm milk into a clean bowl, whisk in all of the Greek yogurt until smooth, then pour this starter mixture back into the remaining three-quarters of the milk in the pot and stir gently to combine.
6. Pour the inoculated milk into the sanitized jar, cover loosely and incubate at 108–112°F (42–44°C), such as in an oven with only the light on or a yogurt maker, for about 6 hours, checking the temperature. Stop as soon as it is softly set and pulls from the side of the jar in one mass when tilted; a shorter incubation keeps it mild and loose.
7. Refrigerate the yogurt immediately at 40°F (4°C) or below and chill at least 4 hours.
8. Whisk the cold yogurt briskly for about 30 seconds until smooth and pourable, then pour into 4 glasses. The yield is about 1 kg, about 1 cup (250 g) per serving, since nothing is drained. Keep refrigerated and use within 1–2 weeks.