Barefoot: Regarding Rejuvilac

Hi, my first post in the forum. I read before that you recommended Rejuvilac (fermented wheat) for a good probiotic live drink. You said that it was really powerful and to start off in small amounts. I was wondering.. can one ferment rye, instead of wheat, and still get the probiotic benefits? Or would it be much less, or does it even matter?
Thanks,
Andy.