Origin of kefir grains

I was just looking at the Wikipedia page for kefir, where it states that

to which the obvious question is, “Then how did we get the first ones?”

Some Googling has yielded primarily “it was a gift from God” to which I must respond, “Okay… what else you got?”

So, anyone have a better explanation than “A miracle occurred?”

nm

Well, there’s no problem for bacteria and yeast to grow in milk. The issue is just finding the right combination that makes a palatable drink. At some point, the right combination was accidentally hit upon.

My guess would be that it’s not impossible to make kefir from scratch, just that the stuff you make from scratch is unlikely to have an optimal mix of bacteria and yeast, and so will end up rather “off”. The grains inoculate the milk with the “right” strains of bacteria and yeast. It’s not unlike a sourdough starter: you can try to produce one from scratch, but once you’ve got a good one, you keep that culture alive and reuse it.

My grandmother used to make bread and somehow she’d get yeast by putting a raisin or dried fruit in water and I guest the bread yeast would live on it and in a few days she’d have yeast.

Or maybe not, that’s how I remember it though. So I guess it’s possible to get yeast and bacteria from the air