I learned the following method from The Kefir Lady. Note it's best to use room temp milk and not cold.
Sorry I'm new at this and haven't voted yet. I'll get it someday. But I notice a question about kefir grains. I'm not sure if you mean water kefir or dairy kefir, but I have water kefir grains. I think you are asking how to make them grow more. When I first got mine I had about a 1/4 cup. I placed them in mineral water (about 3 cups) with white sugar(about a 1/4 cup) and maple syrup (just a little maybe a teaspoon) and a tiny pinch of baking soda and a tiny pinch of sea salt. They really started to grow. I would take the grains out of that water in 2 days and put them in new water with some white sugar but I always added something like some maple syrup, molasses, organic brown sugar - something with minerals in it. The water that I took them out of I would then use to ferment my drink - I like apple and raisins or dried figs or ginger/lemon. I soon had so many grains I had to give some away. I also got tired of doing this so my grains took a break in the frig with these water solutions for a few weeks. Maybe they have slowed down! Also, there is less sugar when they have fermented the drink, but I'm sure there is some sugar left over. Don't know how this jives with paleo.
Once my grains got healthy after being mailed to me (about 4 weeks) they began to double every week. Putting them in progressively larger amounts of milk shoul get them reproducing exponentially, but what are you going to do with all that kefir????