[keiferski]

I don’t have much direct experience with British English but do people really say the soda tastes on to mean the soda tastes fine?

[have_faith]

No we don't say that. We would only say that it tastes off. We really only use the opposite with regards to events, this event is on, Daniell's birthday surprise is on, etc.

[keiferski]

Right, the usage is the same in the US. If an event is proceeding ahead as planned, it’s on.

[furiens]

As well as an event, a drink on tap can be ‘on’ or ‘off’, to refer to its availability.