if you're wondering about Yerba Mate I've got good news, it works. I do a continous feeding cycle, taking off 20% of the kombucha every 2-3 days, then adding that amount back to the fermenter (I've read many good things probiotic-wise doing this). When I feed my culture, I trade off doing Yerba Mate and a cheap Irish breakfast tea (100% assam). I always use an unrefined cane sugar when I feed it as well, to make sure it has enough nutrients.
Primary:Russian River Redemption clone, Kelly's Melomel, Graham's English Cider 22-23
Aging:Public House Dry Stout, Procrastination Porter, Mr. Brown Ale, Westvleteren 12 Clone, Mead, Duvel Clone, Graham's English Cider 6-21, Belgian Draak Strong Ale, Fig Melomel, Acerglyn, Restorative Tonic Metheglyn