Well my first experiment will be with already made beer. 3:1 beer/natural cider vinegar (with mother) under an air lock to control what gets in . Like beer and cider sure you can spontaneous ferment but I'm trying to control off flavors. Another way I've read is to use wort, must, or juice and add champagne yeast and the mother together. The champagne yeast will take off first then the mother all under the control of an airlock. It's alot like making a Bret beer I think.