Combine the milk and the grains in a jar and stir gently.
Place a lid on the jar and tighten it gently.
Place the jar in a warm place where it can rest, undisturbed, for approximately 12 hours.
After 12 hours, place a small strainer over a new container in which you will store the milk kefir. Strain the milk kefir into this container, using the strainer to catch the grains.
You can now drink the milk kefir or refrigerate it to enjoy it cold.
Transfer the kefir grains back into the original jar, add fresh milk, stir, replace the cap, and place the jar in a warm spot where the jar can be undisturbed for 12 hours while the milk cultures into another batch of milk kefir. You can repeat this process indefinitely, making milk kefir every day.