In 1690, English philosopher and physician John Locke wrote about a blind man who longed to understand hues he’d never seen. One day, the man announced that he recognized the color red, finally. “It’s like the sound of a trumpet!” he proclaimed. Some consider this to be the first recorded account of synesthesia, a neurological phenomenon in which a person experiences a sense other than the one that’s being stimulated—the piano note E-flat is lavender; circles taste bitter; confusion is orange.

Neurologists estimate that between two to four percent of the world’s population regularly and consciously experiences synesthesia, but some have argued that crossover between senses—especially color’s link to emotional and physical reactions—might be, at least to an unconscious degree, present in everyone.

“All of us (no matter whether we are synesthetes or not) match basic tastes to colors in ways that are far from arbitrary,” University of Oxford psychologist Charles Spence wrote in a 2015 paper. Research shows that the tendency to pair colors with specific flavors—bitter is black; salty is white or blue; sour is yellow or green; and sweet is pink or red—transcends cultures and eras.

Other scientists have proven the strength of color’s influence on aroma. In 2001, French PhD candidate Frédéric Brochet dyed white wine red before giving it to 54 oenology experts at the University of Bordeaux. Upon tasting the alcohol, they described it exactly as they had described actual red wine the week before, with words such as, “raspberry,” “cherry,” “cedar,” and “chicory.” The connoisseurs could not tell that the wine was actually white.

The findings were shocking, and suggested the esteemed art of wine tasting could be a sham. But should we be surprised? Aroma plays an important role in flavor detection, yet the human sense of smell is relatively weak compared to other mammals. Instead, we rely on visual cues, which hit our brains about ten times faster than olfactory prompts.

“Flavor and color need to complement one another to deliver the intended experience,” says Jody Renner-Nantz, applications manager at DDW The Colour House (a natural food coloring manufacturer). When they don’t, or when there’s a discrepancy between what we see and what we smell or taste, vision usually wins.

The link between color and food is likely rooted in biology. At some point, our ancestors evolved from having two types of color receptors in the retina (“dichromats”) to three types (“trichromats”), allowing them to perceive more wavelengths. Trichromats had an evolutionary advantage, as they could pick out colorful fruits and younger leaves from further distances. Evidence suggests that this improvement in color vision coincided with the deterioration in primates’ sense of smell.

“We associate color and taste starting from birth, and it affects us in ways we don’t always perceive,” says Jenn David Connolly, creative strategist at Jenn David Design. “It can invite us or turn us away, stimulate the appetite, and set a mood,” adds the color expert, who consults with food companies on using color to their advantage when developing products and brands.

Microbes of Many Colors

Molds that live on and in cheese appear in many hues. Some are familiar: Carotenoids are responsible for the red-orange molds such as Fusarium domesticum on washed-rind cheeses. Melanin, a chemical present in human skin that helps safeguard us from the sun’s UV rays, plays a similar protective role in Penicillium molds—melanin creates the blue or green hue found in blue cheeses.

Other molds are more exotic. Tufts University microbiologist Benjamin Wolfe, who studies cheese mold ecology, has seen molds growing on cheese that are white, red, orange, yellow, green, blue, gray, pink, and purple. “Walking into a cheese cave is like walking into a Technicolor natural history museum of mold,” says Wolfe, who blogs about his findings at microbialfoods.org. “It’s one of the most beautiful places to go if you are fascinated by molds . . . Different caves have unique color palettes determined by the community of fungi and bacteria that live in that cave.”

One of Wolfe’s favorite molds is Sporendonema casei, which has a bright orange color, like a highlighter marker. Usually it’s found on natural-rind cheeses from Europe and, for reasons he doesn’t yet understand, the upper Midwest of the US. The neon color may be alarming, but it’s perfectly edible. French affineurs claim Sporendonema casei imparts a mushroomy taste; researchers in that country believe that the mold is found only in dairy ecosystems.

Perhaps the most apt metaphor for a cheese surface dotted with these mysterious molds is an unexplored rainforest, inhabited by all kinds of eye-catching creatures.

Nutritionists have long understood that beyond influencing the mind, food color can affect wellbeing. Talya Lutzker, a Santa Cruz, Calif., dietitian who practices the ancient Indian healing system of Ayurveda, uses color to bring her patients’ bodies back to balance.

“When something’s red, pink, or orange,” Lutzker says, “that implies heat and warmth. So if someone is feeling cold, I’ll recommend that they eat red lentils, not green or black lentils.”

Modern nutrition, too, incorporates color—from a young age, we’re told to eat fruits and vegetables across the color spectrum. And for good reason: Lutein and indoles in green foods lower the risk of some cancers, improve muscular and bone health, and strengthen teeth, while anthocyanins in purple foods improve circulation and prevent aging. Carotenoids in orange and yellow fruits and vegetables have been linked to a lower risk of cancer, heart disease, and blindness.

One of these carotenoids, beta-carotene—which gives carrots an orange color—is also present in grass. When cows eat grass they pass beta-carotene into their milk. The pigment remains hidden in fat globules among protein clusters that scatter visible light, making milk appear white. But cheesemaking disrupts fat membranes and protein clusters, unmasking beta-carotene. The more a cow feeds on fresh grass and the higher fat content of milk, then, the more golden the cheese.

This is why golden color has been linked to cheese quality, and why producers in the 1600s began using red annatto seeds to color cheeses orange. What began as a way to mask lower fat levels (resulting from silage feeding) became a tradition that persists today in orange cheeses including Mimolette, Red Leicester, and many Wisconsin cheddars.

While some consumers might think orange cheddar tastes better than white cheddar, usually the hue comes from colorants with little to no taste. If blindfolded, you probably wouldn’t be able to differentiate the two.

But keep those trichromatic peepers open. Otherwise, you’ll miss visual sensations that add an extra layer of magic to tasting. Embrace the subconscious synesthesia and taste the rainbow: It’s part of what makes eating and pairing foods so much fun.

Molly McDonough

Former Senior Editor Molly McDonough worked for cheesemakers in Switzerland and the US before earning a Master's degree in Agriculture and Food Science at the Ecole Supérieure d'Agriculture in Angers, France. After spending a year in Romania working on rural development projects with Heifer International, she returned home to Boston and joined the culture team in 2015.