@RustyCrab @pwm ime you don't need any kind of special milk. Any kind of milk works as long as it's always been milk (i.e. not reconstituted milk). I've fermented raw milk, boiled milk, ultra high temperature milk, etc. Never an issue.

That said, kefir IS sour, and also has alcohol. i strained it so I never noticed any grains. What do you mean by not being consistent?

Also, for some reason, you can't use metal. Either use glass, plastic or wood for everything. I don't know why, but that's how I learned it from my mother.