Instructions

• Pour all 2 litres of milk into a heavy pot and heat over medium heat, stirring occasionally to prevent scorching, until the milk reaches 195°F / 90°C. Use a thermometer. If you do not have one, stop heating just before the milk boils (as it begins to simmer).
• Remove the pot from the heat and let the milk cool to 110°F / 43°C. Use a thermometer. If you do not have one, test by dipping a clean pinky into the milk and counting to 20 — it should feel warm but not painfully hot at 20 seconds; if it is too hot, let it cool longer.
• Reserve about 1 cup (≈240 ml) of the cooled milk in a small bowl. Add all 245 g of the yogurt to that bowl and whisk until smooth to make a starter slurry.
• Pour the yogurt starter back into the pot with the remaining cooled milk and whisk gently and thoroughly to combine.
• Cover the pot to hold the heat (a lid, then wrap the pot in a blanket or place in a warm insulated spot). Keep the milk-yogurt mixture warm and undisturbed for at least 6 hours. Do not move or shake the pot during this incubation.
• After the incubation period, transfer the pot to the refrigerator and chill, undisturbed, for 24 hours. After 24 hours the yogurt is ready to eat.
• If you want thicker, strained (Greek) yogurt: line a fine-mesh strainer with cheesecloth, place it over a bowl, pour the chilled yogurt into the lined strainer, and let it drain for several hours or until whey stops dripping. You may hang the cheesecloth to speed draining if desired.
• Store unstrained yogurt in the refrigerator for up to 10 days. Straining to remove whey will thicken the yogurt and can extend its refrigerated life by about one additional week.
• Use whole or 2% milk and full‑fat (2% or full) yogurt as the recipe specifies; avoid skim milk. Make sure you reach the correct heating and cooling temperatures and do not disturb the yogurt during incubation.