The Science Behind Why We Crave Loud and Crunchy Foods

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A number of years ago, food giant Unilever polled consumers asking how the company might improve their popular line of Magnum ice cream bars. The problem, respondents said, was that the chocolate coating of the bars tended to fall off too quickly, creating blotches of sticky goo on carpeting. Unilever reacted by changing the recipe to make the chocolate less prone to spills.

When they tested the new and improved product, they expected a warm reception. Instead, they got more complaints than before. While the updated bar didn’t make a mess, it also didn’t make the distinctive crackle that its fans had grown accustomed to. Deprived of hearing the coating collapse and crumble, the experience of eating the ice cream was fundamentally changed. And not for the better.

Smell and taste researcher Alan Hirsch, M.D. refers to it as the “music of mastication,” an auditory accompaniment to the sensory stimulus of eating. “For non-gustatory, non-olfactory stimulation, people prefer crunchiness,” he tells Mental Floss. Humans love crunchy, noisy snacks, that loud rattling that travels to our inner ear via air and bone conduction and helps us identify what it is we’re consuming. Depending on the snack, the noise can reach 63 decibels. (Normal conversations are around 60 dB; rustling leaves, 20 dB.)

When we hear it, we eat more. When we don’t—as in the case of Magnum bars, or a soggy, muted potato chip—we resort to other senses, looking at our food with doubt or sniffing it for signs of expiration. Psychologically, our lust for crispy sustenance is baked in. But why is it so satisfying to create a cacophony of crunch? And if we love it so much, why do some of us actually grow agitated and even aggressive when we hear someone loudly chomping away? It turns out there’s a lot more to eating with our ears than you might have heard.

 
 

The science of crunch has long intrigued Charles Spence, Ph.D., a gastrophysicist and professor of experimental psychology and head of the Crossmodal Research Laboratory at the University of Oxford. Food companies have enlisted him and consulted his research across the spectrum of ingestion, from packaging to shapes to the sound chips make rustling around in grocery carts.

“We’re not born liking noisy foods,” he tells Mental Floss. “Noise doesn’t give a benefit in terms of nutrition. But we don’t like soggy crisps even if they taste the same. Missing the sound is important.”

In 2003, Spence decided to investigate the sonic appeal of chips in a formal setting. To keep a semblance of control, he selected Pringles, which are baked uniformly—a single Pringle doesn't offer any significant difference in size, thickness, or crunch from another. He asked 20 research subjects to bite into 180 Pringles (about two cans) while seated in a soundproof booth in front of a microphone. The sound of their crunching was looped back into a pair of headphones.

After consuming the cans, they were asked if they perceived any difference in freshness or crispness from one Pringle to another. What they didn’t know was that Spence had been playing with the feedback in their headphones, raising or lowering the volume of their noisy crunching [PDF]. At loud volumes, the chips were reported to be fresher; chips ingested while listening at low volume were thought to have been sitting out longer and seemed softer. The duplicitous sounds resulted in a radical difference in chip perception. It may have been a small study, but in the virtually non-existent field of sonic chip research, it was groundbreaking.

A view inside a potato chip bag
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For Spence, the results speak to what he considers the inherent appeal of crunchy foods. “Noisy foods correlate with freshness,” he says. “The fresher the produce, like apples, celery, or lettuce, the more vitamins and nutrients it’s retained. It’s telling us what’s in the food.”

Naturally, this signal becomes slightly misguided when it reinforces the quality of a potato chip, a processed slab of empty calories. But Spence has a theory on this, too: “The brain likes fat in food, but it’s not so good at detecting it through our mouths. Noisy foods are certainly fattier on average.”

Fatty or fresh, raising decibels while eating may also have roots in less appetizing behaviors. For our ancestors who ate insects, the crunch of a hard-bodied cricket symbolized nourishment. In a primal way, violently mincing food with our teeth could also be a way to vent and dilute aggression. “There are some psychoanalytic theories related to crunchiness and aggressive behavior,” Hirsch says. “When you bite into ice or potato chips, you’re sublimating that in a healthy way.”

 
 

All of these factors explain why crunch appeals to us. But is it actually affecting what we taste?

Yes—but maybe not the way you’d think. “Sound affects the experience of food,” Spence says. “The noise draws attention to the mouth in the way something silent does not. If you’re eating pâté, your attention can drift elsewhere, to a television or to a dining companion. But a crunch will draw your attention to what you’re eating, making you concentrate on it. Noisy foods make you think about them.”

That crunch can also influence how much food we consume. Because noisy foods tend to be fatty, Spence says, they’ll retain their flavor longer. And because the noise reinforces our idea of what we’re eating, it affords us a sense of security that allows us to keep consuming without having to look at our snack—not so important in a brightly-lit room, but crucial if we’re in a dark movie theater. “It becomes more important when you can’t see what you’re eating,” Spence says.

Thanks to this hard-wired feedback, the snack industry has made it a priority to emphasize the sounds of their foods in both development and marketing. In the 1980s, Frito-Lay funded extensive work at a Dallas plant that involved $40,000 chewing simulators. There, they discovered the ideal breaking point for a chip was four pounds per square inch (PSI), just a fraction of what we might need to tear into a steak (150 to 200 PSI). The quality and consistency of the potatoes themselves is also key, according to Herbert Stone, Ph.D., a food scientist who has worked with companies on product development. “Too thick, too hard, and people don’t like them,” Stone tells Mental Floss. “Too thin and they just crumble.”

The right potato sliced at the right thickness with the right oil at the right temperature results in a solid chip—one resilient enough to make for a satisfying break when it hits your molars, but vanishing so quickly that your brain and body haven’t even processed the calories you’ve just taken in. “If they pick it up and put it in the mouth and the crunch is not what they expect, they might put it down,” Stone says. “It’s about expectation.”

A shopper examines a bag of potato chips
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Walk down the snack aisle in your local supermarket or glance at commercials and you’ll find no shortage of claims about products being the boldest, crunchiest chip available. For years, Frito-Lay marketed Cheetos as “the cheese that goes crunch!” Even cereals try to capitalize on the fervor, making mascots—Snap, Crackle, and Pop—out of the sound their Rice Krispies make when submerged in milk. One ad for a brand of crisps drew attention for “cracking” the viewer’s television screen.

For most consumers, the promise of sonic flavor will draw their attention. But for a small number of people diagnosed with a condition dubbed misophonia, the sound of a co-worker or partner crunching on chips isn’t at all pleasurable. It’s insufferable.

 
 

According to Connecticut audiologist Natan Bauman, M.D., the average noise level of someone masticating a potato chip is between 25 to 35 decibels. (Other sources peg it as closer to 63 dB when you're chewing on a chip with your mouth open, or 55 dB with your lips closed.) When you hear your own chewing, the sound is being conducted both via the air and your own bones, giving it a distinctively unique sound. (Like talking, hearing yourself chewing on a recording might be troubling.)

For someone suffering from misophonia, or the literal hatred of specific sounds, it's not their own chomping that's the problem. It's everyone else's.

When we chew, Bauman says, the auditory cortical and limbic system areas of our brain are lighting up, getting information about freshness and texture. But people with misophonia aren’t struggling with their own sounds. Instead, they're affected by others typing, clicking pens, or, more often, chewing. The sound of someone snacking is routed from the cochlea, or cavity in the inner ear, and becomes an electric signal that winds up in the brain’s amygdala, which processes fear and pleasure. That's true for everyone, but in misophonics, it lands with a thud. They’ve likely developed a trigger, or negative association, with the sounds stemming from an incident in childhood.

“If you are scolded by a parent and they happen to be eating, or smacking, it becomes negative reinforcement,” Bauman says. Chewing, lip smacking, and even breathing become intolerable for sufferers, who often feel agitated and nervous, with corresponding increases in heart rate. Some fly into a rage.

Misophonics don’t necessarily recoil at all of these sounds all of the time: It may depend on who’s doing the snacking. Often, it’s a co-worker, spouse, or family member munching away that prompts a response. Fearing they’ll damage that relationship, sufferers tend to vent online. The misophonia subreddit is home to threads with titles like “And the popcorn eater sits RIGHT next to me on the plane” and “Chips can go f-ck themselves.” (The entire content of the latter: “F-ck chips, man. That is all.”)

Bauman says misophonia can be treated using cognitive therapy. An earpiece can provide white noise to reduce trigger sounds while sufferers try to retrain their brain to tolerate the noises. But even the sight of a bag of chips can be enough to send them scrambling.

People with misophonia might also want to exercise caution when traveling. Although some Asian cultures minimize crunchy snacks because loud snacking is considered impolite, other parts of the world can produce noisier mealtimes. “In parts of Asia, you show appreciation for food by slurping,” Spence says. Slurping is even associated with a more intense flavor experience, particularly when it’s in the setting of a comparatively quiet dining establishment.

Western culture favors noisier restaurants, and there’s a good reason for that. Supposedly Hard Rock Café has mastered the art of playing loud and fast music, resulting in patrons who talked less, ate faster, and left more quickly, allowing operators to turn over tables more times in an evening.

Spence believes sound will continue to be important to gastronomy, to chefs, and to food companies looking to sell consumers on a complete experience. Snack shelves are now full of air-puffed offerings like 3-D Doritos and Pop Chips that create pillows of taste. With less volume, you’ll snack more and crunch for longer periods.

A woman snacks on a chip
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But the sound of the chip is just one part of the equation. The way a bag feels when you pick it up at the store, the aroma that wafts out when you first open the bag, the concentration of flavor from the granules of seasoning on your fingers—it’s all very carefully conducted to appeal to our preferences.

“When we hear the rattle of crisps, it may encourage people to start salivating, like Pavlov’s dogs,” Spence says, referring to the Russian scientist who trained his canines to salivate when he made a certain sound. We’re conditioned to anticipate the flavor and enjoyment of chips as soon as we pick up a package. Even hearing or saying the words crispy and crunchy can prime us for the experience.

When we’re deprived of that auditory cue, we can get annoyed. After news reports emerged that Pepsi CEO Indra Nooyi had mentioned her company might consider a quieter version of Doritos for women—an idea PepsiCo later denied they would label in a gender-specific fashion—women Doritos enthusiasts rallied around the Texas state capitol, condemning the perceived gender discrimination. To protest the possible dilution of their favorite snack, they made a spectacle of crunching Doritos as loudly as they could.

This Macaroni and Cheese Meatball Recipe Is Easy Enough to Make in a Dorm Room

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iStock.com/LauriPatterson

It's hard to make creative meals when you're working out of a dorm "kitchen," but Daniel Holzman, the chef/co-owner of The Meatball Shop in New York City, proves that college students don't need to limit themselves to energy drinks and instant ramen noodles. Using just a coffee maker and a toaster oven, he's found a way to prepare an easy recipe for macaroni and cheese meatballs.

The video below is the fourth episode of "The College Try," a new series from Food & Wine and Spoon University that challenges chefs to create meals using dorm equipment and ingredients. Holzman starts by "brewing" his macaroni in a coffee maker. Once the pasta is cooked, he stirs in one tablespoon of butter and transfers it to a plate. To start making the cheese sauce, he adds two cups of milk and two tablespoons of butter to the coffee pot before retuning it to the warm burner.

Holzman prepares the meatballs by mixing ground beef, breadcrumbs, cheddar cheese, salt, and the cooked macaroni in a bowl. After he shapes the meat mixture into 2-inch balls, he bakes them in a toaster oven preheated to 450°F for 12 minutes.

The last step is the sauce. The chef whisks a packet of cheese powder from a box of macaroni and cheese into the milk and uses that as the base for his plate of meatballs. In about half an hour, he makes a meal that looks a lot better than what you can find in most college dining halls.

From microwaved omelets to mug cakes, here are some more cooking hacks for dorm life.

[h/t Spoon University]

Eliza Leslie: The Most Influential Cookbook Writer of the 19th Century

American cookbook author Eliza Leslie
American cookbook author Eliza Leslie
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If it wasn't for Eliza Leslie, American recipes might look very different. Leslie wrote the most popular cookbook of the 19th century, published a recipe widely credited as being the first for chocolate cake in the United States, and authored fiction for both adults and children. Her nine cookbooks—as well as her domestic management and etiquette guides—made a significant mark in American history and society, despite the fact that she never ran a kitchen of her own.

Early Dreams

Born in Philadelphia on November 15, 1787, to Robert and Lydia Leslie, Eliza was an intelligent child and a voracious reader. Her dream of becoming a writer was nurtured by her father, a prosperous watchmaker, inventor, and intellectual who was friends with Benjamin Franklin and Thomas Jefferson. She once wrote that "the dream of my childhood [was] one day seeing my name in print."

Sadly, her father’s business failed around the turn of the 19th century and he died in 1803. The family took in boarders to make ends meet, and as the oldest of five, Leslie helped her mother in the kitchen. To gain culinary experience, she attended Mrs. Goodfellow’s Cooking School in Philadelphia, the first school of its kind in the United States. Urged by her brother Thomas—and after fielding numerous requests for recipes from friends and family—she compiled her first book, Seventy-Five Receipts for Pastry, Cakes, and Sweetmeats, in 1828. Notably, the book included the term cup cake, referring to Leslie's employment of a teacup as a measuring tool ("two large tea-cups full of molasses")—possibly the first-ever mention of a cup cake in print.

Seventy-Five Receipts was a hit, and was reprinted numerous times. Encouraged by this success—and by her publisher, Munroe & Francis—Leslie moved on to her true desire: writing fiction. She penned short stories and storybooks for young readers as well as adult fiction and won several awards for her efforts. One of her prize-winning short stories, the humorous "Mrs. Washington Potts," appeared in Godey’s Lady’s Book, the popular 19th century magazine for which she also served as assistant editor. Leslie also contributed to Graham’s Magazine, the Saturday Gazette, and The Saturday Evening Post. At least one critic called her tales "perfect daguerreotypes of real life."

As much as Leslie loved writing fiction, however, it didn't always pay the bills. She wrote a second cookbook, Domestic French Cookery, in 1832, and achieved the pinnacle of her success in 1837 with Directions for Cookery. That work became the most beloved cookbook of the 1800s; it sold at least 150,000 copies and was republished 60 times by 1870. She offered pointers on procuring the best ingredients ("catfish that have been caught near the middle of the river are much nicer than those that are taken near the shore where they have access to impure food") and infused the book with wit. In a section discouraging the use of cold meat in soups, she wrote, "It is not true that French cooks have the art of producing excellent soups from cold scraps. There is much bad soup to be found in France, at inferior houses; but good French cooks are not, as is generally supposed, really in the practice of concocting any dishes out of the refuse of the table."

In The Taste of America, noted modern food historians John and Karen Hess called Directions for Cookery “one of the two best American cookbooks ever written," citing the book's precise directions, engaging tips, straightforward commentary, and diverse recipes—such as catfish soup and election cake—as the keys to its excellence.

Leslie is also credited with publishing America’s first printed recipe for chocolate cake, in her 1846 Lady’s Receipt Book. While chocolate had been used in baking in Europe as far back as the 1600s, Leslie’s recipe was probably obtained from a professional chef or pastry cook in Philadelphia. The recipe, which featured grated chocolate and a whole grated nutmeg, is quite different from most of today's chocolate cakes, with its strong overtones of spice and earthy, rather than sweet, flavors. (You can find the full recipe below.)

Later in life, while continuing to write cookbooks, Leslie edited The Gift: A Christmas and New Year’s Present, which included early publications by Edgar Allan Poe. She also edited her own magazine of literature and fashion, Miss Leslie’s Magazine. She wrote only one novel, 1848's Amelia; Or a Young Lady’s Vicissitudes, but once said that if she was to start her literary career over, she would have only written novels.

A Uniquely American Voice

Historians have argued that Leslie was successful because she crafted recipes to appeal to the young country’s desire for upward mobility as well as a uniquely American identity. At the time she began writing, women primarily used British cookbooks; Leslie appealed to them with a distinctly American work. (She noted in the preface to Seventy-Five Receipts, "There is frequently much difficulty in following directions in English and French Cookery Books, not only from their want of explicitness, but from the difference in the fuel, fire-places, and cooking utensils. ... The receipts in this little book are, in every sense of the word, American.")

Leslie included regional American dishes in her books, promoted the use of quality ingredients, and was the first to (sometimes) organize recipes by including ingredients at the beginning of each recipe instead of using a narrative form, setting the tone for modern recipe writing. Her books were considered a treasure trove of knowledge for young pioneer women who, frequently separated from their families for the first time, often relied on Leslie's works for guidance.

Unmarried herself, Leslie never managed her own kitchen, and often had others testing recipes for her. She maintained strong ties with her erudite, sophisticated family, and lived for a time with her brother Thomas while he was attending West Point. Another brother, Charles Leslie, was a well-regarded painter in England; her sister Anna was also an artist, and sister Patty was married to a publisher who produced some of Leslie’s work. As she got older, Leslie lived for years in the United States Hotel in Philadelphia, where she was something of a celebrity for her wit and strong opinions.

Leslie died on January 1, 1858. Many of her recipes are still used today, but it's likely she’d be most pleased to know that many of her short stories are available online. Modern readers can appreciate the totality of her work: the fiction writing that was her passion, though for which she was lesser known, and her culinary writing, which guided generations.

Eliza Leslie's Recipe for Chocolate Cake

From The Lady's Receipt Book:

CHOCOLATE CAKE.—Scrape down three ounces of the best and purest chocolate, or prepared cocoa. Cut up, into a deep pan, three-quarters of a pound of fresh butter; add to it a pound of powdered loaf-sugar; and stir the butter and sugar together till very light and white. Have ready 14 ounces (two ounces less than a pound) of sifted flour; a powdered nutmeg; and a tea-spoonful of powdered cinnamon—mixed together. Beat the whites of ten eggs till they stand alone; then the yolks till they are very thick and smooth. Then mix the yolks and whites gradually together, beating very hard when they are all mixed. Add the eggs, by degrees, to the beaten butter and sugar, in turn with the flour and the scraped chocolate,—a little at a time of each; also the spice. Stir the whole very hard. Put the mixture into a buttered tin pan with straight sides, and bake it at least four hours. If nothing is to be baked afterwards, let it remain in till the oven becomes cool. When cold, ice it.

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