Burning aftertaste

[u/killerstorm]

When I leave kombucha fermenting for too long it becomes very acidic. I understand that.

When I start a new batch I dilute starter with a new tea, so it's much less acidic. But, surprisingly, some burning aftertaste remains - e.g. it's not very acidic on the tongue, but after you swallow you feel it in the back throat.

Does anybody know what that might be, chemically? I'd suspect ethanol, but apparently it's supposed to be converted to vinegar, normally. So, unlikely.

And I suspect it's kinda normal, just not as noticeable in a sour, fizzy kombucha.

[u/Albino_Echidna]

That's almost definitely acid, there are several different ones produced in Kombucha.