I've been making kefir (very simple - dump milk on kefir grain / culture, let sit a day at room temp, strain them out), and blending it with some frozen fruit (mangos or raspberries), a little sugar, and some creatinine (which is in shakeology, and can be bought from Amazon cheaply). Sometimes I'll swap the sugar for a ripe banana, but my understanding for a post-workout drink is that you want some simple sugars for recovery. I haven't tried adding whey, but that would be a logical addition.