When I was a kid, I learned that there were four distinct tastes: sweet, sour, salty, and bitter. There is a fifth taste, umami, which is basically that savory sensation described by the Japanese. Apart from these five, researchers are saying that there is a sixth. Or, to be more precise, we can divide the salty taste into two different sensations: one where the saltiness is just right and you can enjoy the flavor of the food being accentuated by the salt, and the other when there's too much salt and you feel repulsed.
In the case of salt, scientists understand many details about the low-salt receptor, but a complete description of the high-salt receptor has lagged, as has an understanding of which taste bud cells host each detector.
“There are a lot of gaps still in our knowledge — especially salt taste. I would call it one of the biggest gaps,” says Maik Behrens, a taste researcher at the Leibniz Institute for Food Systems Biology in Freising, Germany. “There are always missing pieces in the puzzle.”
In our culture, we have a condiment made of fermented fish or shrimp paste with salt. If you eat a handful of that, it tastes awful. It's not exactly bitter, but it's a repugnant taste. That's what high levels of salt must taste like. It's not salty the way we would define salty. It's a whole class altogether, and I think that's what taste researchers are looking into. Although, not everybody is convinced. Amber Dance writes about these nuances on Knowable.
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