To answer your question "what's this rehydrating i hear about", the kefir grains that you got from Uny and I have been dehydrated. Before you can use them to make your water kefir, they must first be plumped back-up or re-hydrated. Just soak them in some spring water for 4-8 hours and you should be good to go. Be sure to drain the water from the grains before you make your kefir. Hope that answered your question.