Why Do Batteries Taste Sour?

The video explains why a 9-volt battery tastes sour when touched to the tongue, due to the electrical current causing electrolysis in saliva. This process creates hydrogen ions, which activate sour taste receptors. Different electrical currents can produce various tastes, such as sweet or bitter, depending on the current and temperature. Scientists have experimented with electric taste to mimic flavors, but recreating complex flavors remains challenging. The video concludes with a caution against licking batteries.

What new insight or understanding did you gain from this video?