Most of us have been taught that salty, sweet, sour, and bitter (that last one added by Greek philosopher Democritus a few thousand years ago) make up the four building blocks of taste. But since the "savory" taste (also called umami) was added as a fifth taste about a decade ago, the list is expanding—and rapidly—as scientists better understand how we taste; there could be as many as 20 other candidates, the New York Times reports. So how does this all work? When food enters our mouths, chemicals pass over our taste buds and help us differentiate between items that are nutritious (which tend to register as pleasant) and poisonous (which tend to cause revulsion).
Some tastes are registered unconsciously, while many are more conscious, set apart by having their own sets of receptor cells. Molecular biologists began to learn which cells in our mouths detect bitter and sweet tastes about 15 years ago; in the past few years, they've proposed receptor cells on the tongue dedicated to calcium, water, carbonation, soapiness, electric, alkaline, and metallic, among others. The next big contender? Fattiness, previously dismissed as just a texture. Coolness (think peppermint) and piquance (think hot peppers) are also proposed, reports Business Insider. "The taste field has been absolutely revolutionized,” one biologist says. "We’ve made more progress in the last 15 years than in the previous 100." (As for scents, check out exactly why bacon smells so good.)