They're different. She's not making kefir with piima, she's making piima. Some people use the term "kefir" for any cultured milk product of drinkable consistency (not as thick as yogurt). I don't know how they compare in terms of the range of organisms, I suspect that kefir has more, but piima is certainly also a beneficial food in terms of probiotics. Piima is not a scoby like kefir, meaning it's not a separate "thing" that you put into the milk to culture it that remains separate and gets strained out to put in the next batch of fresh milk. Piima is cultured more like yogurt because you retain some of the cultured product to add to the next batch of milk, like you would do with yogurt. I haven't tasted piima, but I have read it's less tart than kefir. You could definitely use it to make a cultured milk product used in the same way as kefir (for drinking, soaking grains, making a cream cheese type of thing, obtaining whey, etc.). I make fil mjolk, which I've read is very similar to piima in flavor and texture, but that piima is more slimey - the texture of fil mjolk is nearly identical to storebought buttermilk. I've also read the piima culture is more temperature sensitive than fil mjolk or kefir, that it tolerates a smaller range of temps in which it will ferment well. I've found fil mjolk and kefir to both be very forgiving of the temp, meaning anywhere from mid-60s to mid-80s (the usual temp range of my house).
