Contrary to popular belief, the tongue does not have specific areas that detect each type of taste. Instead, basic tastes can be picked up by taste buds on various parts of the tongue, though different cells may have varying levels of sensitivity to sweet, sour, salty, bitter, and umami.
While taste begins in the mouth, flavor is what registers in the brain when it combines the entire experience of taste, texture, temperature, and aroma. “Taste and smell do interact in the brain to put together flavor,” says Richard Mattes, distinguished professor of nutrition science at Purdue University, “but that’s different from taste.”
The process of getting a new taste sensation accepted by the scientific community is complicated. “There is no widely agreed upon set of seven criteria and if you tick each box, you’ve got it,” Mattes says. “It’s just scientific consensus.”
Even so, various criteria have been proposed over the years. For starters, a taste needs to have a “chemical signature”—a set of chemical stimuli that are distinct from that of other substances. Then, Mattes says, you need to have a receptor anywhere on the tongue, palate, or throat where the chemical stimulus can interact with a cell in a taste bud.
That cell in the taste bud must then have a mechanism “to change the stimuli’s chemical signal to an electrical signal that is subsequently transmitted through nerves to the brain,” Mattes adds.