The science behind sour

Do you enjoy sour flavors? I can’t get enough of them, whether it’s pucker-y pickles, astringent sumac, sharp sauerkraut, tangy citrus, or another piquant essence. Sour is one of the essential tastes (alongside sweet, salty, bitter, and umami), although of the five it is the least understood. The Atlantic’s Katherine J. Wu takes a closer look at the reasons so many people love sour food, searching for reasons that explain the paradox of sour.

Scientists have been able to determine why humans have evolved to seek out sweet, salty, and umami-rich foods while generally avoiding bitter flavors. But to date, they have not figured out why our palates can differentiate sour tastes. Research has not yet unearthed an evolutionary reason for us to identify sour foods. “We don’t need sour to live,” Ann-Marie Torregrossa, a taste researcher at the University at Buffalo, explained to Ms. Wu. “It’s a weird sense to need.”

Humans are not alone in tasting sour foods – almost every vertebrate animal retains the ability to suss out acidic flavors – and we aren’t alone in enjoying it, either. But learning why this trait has survived is a difficult task. Researchers have toyed with various theories, such as the fact that sour can denote a food rich in vitamin C, and fermented foods might indicate “that a bonanza of beneficial microbes have colonized our cuisine and started to break its carbohydrates down.” Whatever the biological adaptation turns out to be, I am glad we have retained our ability to identify and enjoy sour foods.