Milk Kefir

Equipment

• Clean 1-quart glass jar
• Loose-fitting lid
• Nonreactive fine-mesh strainer
• Food-safe pH meter
• Controlled-temperature incubator

Instructions

1. 1

   Wash hands and clean the jar, lid, strainer, and utensils thoroughly. Put the active kefir grains in the jar and add the pasteurized milk.

   ⏱ 5 min

2. 2

   Cover loosely so gas can escape. Incubate at the temperature specified by the grain supplier, commonly 68 to 75 F, using a controlled environment rather than a counter with large temperature swings.

   ⏱ 1440 min

3. 3

   Begin checking after 18 hours. The milk should smell cleanly tart and thicken slightly. Measure with a calibrated food-safe pH meter and continue only until it reaches pH 4.6 or lower, usually within 18 to 24 hours.

   ⏱ 5 min

4. 4

   If the milk does not reach pH 4.6 within 48 hours, discard the milk without tasting it and consult the culture supplier before reusing the grains. Also discard a batch with mold, pink or orange color, a rotten odor, or unusual slime.

   ⏱ 2 min

5. 5

   Strain the kefir into a clean container, reserving the grains for the next batch. Refrigerate the finished kefir immediately at 40 F or colder. It is not shelf stable.

   ⏱ 5 min

6. 6

   Keep the kefir covered and refrigerated and use within 7 days. Start the next batch with fresh pasteurized milk, or store the grains according to the supplier's instructions if pausing.

   ⏱ 2 min