I've been fermenting all sorts of stuff for a few years now and I'm quite open to experimentation to the point of being somewhat adventurous.

A jar of low sugar quince marmalade sweetened with grape juice (supermarket product, not homemade) started smelling slightly alcoholic and I filled it with water and left it on the counter to wash out later. Forgot it, found it again after a week and it was happily bubbling away. As I love fizzy drinks in summer I decided to feed it with sugar and bits of lemon and ginger and keep it going. It now lives in my fridge and provides one fresh drink a day.

No adverse effects (so far) and I'm very pleased with my new fermenting friend, but I'm curious about what it is. It doesn't grow a scoby, it's most likely not kombucha. The bottom of the jar has a cloudy layer which seem to be the remains of the marmalade. Ginger bug? Something else?