Pour the milk into several clean, sterilized jars, leaving at least an inch of space at the top. I use three quart (~1 L) jars.
Add the kefir starter, dividing it evenly between jars.
Stir gently to mix, then cover the jar loosely with a lid or cloth.
Ferment at 100°F (38°C) for 24 hours. Use a yogurt maker, an Instant Pot set to yogurt mode, or a dehydrator.
When done, refrigerate until chilled (don’t stir prior).
Optional: strain through a cheesecloth or yogurt strainer for a Greek-style yogurt.
Video
Notes
-This yogurt is thicker and milder than kefir, but it contains more probiotic diversity than most store-bought yogurts.-After the first batch, you can use a few spoonfuls of your kefir yogurt as a starter for 4–6 more batches before starting over with fresh kefir.-A 24-hour fermentation makes the yogurt lower in lactose and higher in probiotic counts.