yes, we've almost finished the qt. ds likes it, but it's too sweet for me (I'm not used to sugar, even fruit sugar, I guess)...it's a tiny bit syrupy and the mango chunks are great (they taste like mango hooch
it didn't get fizzy at all and it was in the cabinet for two days and the fridge about 2 days, too, in just a glass qt jar with a screw on metal lid with the little rubberized area.
I have three gallons brewing right now
and I may have found someone IRL who wants a SCOBY!!
flavoring it was fun, but the mango expanded to about 1/3 of the jar so maybe I just got excited and put too much?
I don't know how to tell if it's "contaminated" for sure...I think it'll either smell so bad you won't drink it (b/c it's probably dangerous) or it'll taste "off" and you'll know that your balance of bacteria and yeast is out of whack
As far as the towel getting soaked, I use very clean prefolds (we used them as burp cloths ages ago) and I've had one get soaked. it didn't cause any problems