A friend who is good at making kefir sent me grains in the mail a few years ago. I did make it with regular store milk, we have good milk around here, and no matter what I did it was not like Nancy’s or other kefir that is smooth. It was slightly grainy or curdley looking; just slightly. Asked friend and she said that’s how home made kefir turns out, I think she blends hers or something. After several tries I gave up and just stick to making yogurt.
Mine never turns out grainy, just thick like a heavy milkshake.