I added scoby to jar of Simple Truth coconut water. This brand appears to have quite a bit less sugar than other brands (even the unsweetened ones), so I wasn’t sure if I would need to add sugar to get it working. I decided to leave it for a week or two, and play it by ear. Most recipes for fermented coconut milk are either CW + water kefir grains, or CW + <your favorite probiotic capsule>, so I hoped CW + scoby will work just fine.
After 6 days the was pH 3.6. That was quick. It’s mildly sour, but could use some sweetness. Drinkable, but not that nice for me. Of course, I don’t like coconut, and thought the original coconut milk tasted horrible (though not like coconut), so it might be fine for others. My brother and his wife drink coconut water (and like coconut), so I give it to them with the understanding that he’d comment here with notes on how it turned out.
I’m guessing that it would be more balanced if the initial CW has been sweeter. With that in mind, I think it might be better sweetened with honey, or with some sort of fruity secondary fermentation. I’ve never attempted or even researched secondary, but he has, so maybe that will work out for him. :)
The interesting thing for me is simply that it works, and works very quickly compared to my usual kombucha fermentation. If you like coconut water and have an interest in fermented foods, give it a try.