why does flat unflavored seltzer water not taste like pain water?

Question

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In: 2

Answer 1

Because carbonated water still has residual carbonic acid dissolved in it, which gives the flat seltzer water it’s odd flavor.

CO2 + H2O ↔ H2CO3

Answer 2

Carbon dioxide reacts with water and produces carbonic acid. So anything carbonated MUST contain carbonic acid, which you can taste when there are no other acids or flavours present.