The Optimal Time to Dunk an Oreo, According to Science

iStock // Lucy Quintanilla
iStock // Lucy Quintanilla

Have you submerged an Oreo into a glass of milk and lingered too long? Did you watch in horror as America's supposedly favorite cookie disintegrated before your very eyes? Fear no more! Here's how to find (and elongate) your optimal dunk time.

THE SHORT ANSWER

Dip your cookie for three seconds, give or take. Carry on with your life, dear reader.

THE LONG ANSWER

Well, it depends. Do you prefer a crispy cookie masked in a thin veneer of milk? A cookie that has metamorphosed into unrecognizable gloop? Do you believe in a Goldilocks zone, a Platonic middle-ground that’s neither too dry, nor too spongy, but just right? It’s all subjective. But let’s assume you want an Oreo that is pleasantly soggy and has maintained its structural dignity.

There’s math for that. In the late 1990s, Len Fisher, then a professor of physics at the University of Bristol, sparked a media storm when he argued that a decades-old mathematical formula could predict the perfect dunk time for a cookie. It’s all thanks, he claimed, to capillary action.

Water molecules are adhesive: They cling to solid surfaces. (It’s why water in a beaker shows a meniscus—it’s attracted to the sides of the container.) When water enters a small tube, the liquid can adhere to surfaces in ways that seem to defy gravity: This is why water may crawl up your drink’s straw and why a paintbrush seems to slurp up liquid. That’s capillary action in a nutshell.

On a microscale, a cookie is essentially a series of small, starchy tubes. Fisher writes in his book How to Dunk a Doughnut that a dunking liquid (in our case, milk) is “held in place in the porous matrix by the pressure across the meniscus in the smallest of pores.” In other words, capillary action helps the milk spread through the cookie. In the early 20th century, the American scientist E.W. Washburn cooked up a formula to describe this watery journey.

Washburn's Equation
Lucy Quintanilla

Washburn tested and confirmed his formula by observing ink blots spread through paper. (A simplified version of his equation explains how inkjet printers spit out dry, sharp-looking text.) But it took nearly a century for someone such as Fisher to apply the formula to baked goods: After finding reliable numbers for the variables, Fisher rearranged the equation and solved for T (time).

He discovered that the perfect dipping time for a typical British dunking biscuit with a conventional dip was three-and-a-half to five seconds.

But Fisher never tested Oreos. So in 2016, members of Utah State University’s Splash Lab—an academic group studying the behaviors of fluids—put Oreos to the test. (Splash Lab, we should note, has an appetite for quirky experiments: They’ve studied the fluid dynamics of urinal splashback, analyzed the physics of the perfect skipping stone, and even tested the insulating properties of beards.)

Three researchers gathered Oreos, Chips Ahoy, Nutter Butter, and Graham Crackers and dipped the cookies halfway in 2 percent milk for half a second to seven seconds. After dunking, the team weighed the treats and measured how much milk had been absorbed.

The results: Oreos absorbed 50 percent of their potential liquid weight in just one second. After two seconds, they absorbed 80 percent. The number flatlined briefly for a second. After the fourth second, the cookie maxed out: It absorbed all its possible milk. “This data indicates that for the tested cookies, keeping your cookie in the glass any longer than five seconds does not lead to any additional milk entering the cookies,” their study suggested.

A graph of optimal cookie dunk times.
Oreo cookies absorbed milk at the same rate as Nutter Butter, taking in 100 percent of their liquid weight in four seconds.
Splash Lab

Splash Lab then performed a second test, dunking all cookies for six seconds and attaching them horizontally to a clamp. They waited for the cookies to collapse. The Oreo lasted an impressive five minutes! Compare that to measly Graham Crackers, which crumbled after eight seconds.

The takeaway: Three seconds is enough time to saturate most of an Oreo. There’s no benefit to dunking longer than four seconds. (Unless you want to watch the cookie crumble into your milk. As Splash Lab’s Randy Hurd, a mechanical engineering Ph.D. candidate, told us: “Waiting for the crisp cookie structure to break down is not necessarily a waste of time if that’s what you prefer.” We don’t judge.)

However, things get more complicated if you choose a different kind of dairy.

THE LONGER ANSWER

Your choice of milk could change the optimal dunk time by a few split seconds.

In 2011, researchers published a study in the Journal of Food Science that explained why milk doesn’t immediately turn breakfast cereal into mush: Fats and other solids in the dairy hindered “liquid infiltration,” slowing absorption. The same process is true of cookies, says Jennifer Fideler, a graduate student in food science at North Carolina State University.

Milk, for one, is full of sugars. Sugars are hygroscopic, meaning they hold onto moisture and can prevent liquid from seeping into the cookie. Additionally, fat and carbohydrate molecules are big. They can prevent the water in the milk from infiltrating the cookie’s porous matrix.  “Not only is it likely that the fat content of the milk (whole, 2 percent, skim, even heavy whip!) would affect the rate of moisture migration ... but the fat included in the cookie—and even moreso the cream filling—would help resist the influx of fluid,” Fideler wrote in an email.

Fat content doesn’t just slow down absorption time. It’s also known to enhance the flavor. In 1999, Len Fisher tested more than 200 British biscuit and drink combinations and concluded that milk could make a cookie 11 times more flavorful. (This wasn’t peer-reviewed, and it was sponsored by a biscuit company, so take it for what it’s worth.) “Milk is essentially fat droplets suspended in water and those fat droplets stay around in your mouth and they hang on to the flavour in the biscuit so that the aroma can be released up to the back of your nose,” Fisher told the BBC.

So, if you’re the type of person who dreams of extending the optimal Oreo dunk time while enhancing the flavor, toss the skim milk down the drain and pour a cup of high-fat dairy. Whole milk (3.25 percent butterfat) spiked with half-and-half (generally 10 percent butterfat) could extend your dunk time. But if you wanted to indulge and throw a Hail Mary—and have a few spare notches left in your belt—try dunking in heavy cream (36 percent butterfat). Heck, while we’re at it, why not go all the way and dip it in melted butter (80 percent butterfat).

(We’d like to take this moment to say we are not licensed to give nutritional advice and are not liable for culinary crimes against humanity. So maybe don't do this.)

THE MUCH LONGER ANSWER

If you wanted to boost the optimal Oreo dunk time even longer, there’s another principle you can hack: Water Activity.

Water activity is a measurement of how likely something gives away moisture. It’s measured on a scale from 0 to 1: Milk, for example, possesses a high water activity of 0.98. It readily gives its water away. A cookie, on the other hand, has a water activity hovering around 0.3. It holds onto its moisture and is more likely to absorb water.

Food manufacturers and processors have to constantly contend with water activity. It’s critical in determining a product’s safety, stability, and shelf life: Controlling water activity is the easiest way to prevent—and predict—the spread of dangerous bacteria [PDF]. (That’s because items with a high water activity are more likely to give water away to nasty microorganisms, causing spoilage.)

But for our selfishly sweet-toothed purposes today, water activity is just another factor affecting the critical cookie dipping time. A liquid with a lower water activity will hold onto its moisture more tightly than standard milk, Fideler explains. So, if you wanted to extend the optimal dunk time further, you should try to dip your Oreo into dairy that not only contains lots of fats and carbs, but also possesses a relatively low water activity. With that in mind, we have the perfect recommendation: Sweetened condensed milk. (We don’t actually recommend this.)

Boasting a high butterfat content (8 percent), obscene loads of carbs (166 grams per cup), and a relatively low water activity (.87), sweetened condensed milk is perfect if you’re the kind of person who relishes long dunk times and believes “calories” are just another government conspiracy designed to scare you from chugging modernity’s decadent ambrosias.

Dunk away!

This story originally ran in 2017.

New Jersey's Anthony Bourdain Food Trail Has Opened

Neilson Barnard/Getty Images
Neilson Barnard/Getty Images

Before Anthony Bourdain was a world-famous chef, author, or food and travel documentarian, he was just another kid growing up in New Jersey. Earlier this year, Food & Wine reported that Bourdain's home state would honor the late television personality with a food trail tracing his favorite restaurants. And that trail is now open.

Bourdain was born in New York City in 1956, and spent most of childhood living in Leonia, New Jersey. He often revisited the Garden State in his books and television shows, highlighting the state's classic diners and delis and the seafood shacks of the Jersey shore.

Immediately following Bourdain's tragic death on June 8, 2018, New Jersey assemblyman Paul Moriarty proposed an official food trail featuring some of his favorite eateries. The trail draws from the New Jersey episode from season 5 of the CNN series Parts Unknown. In it, Bourdain traveled to several towns throughout the state, including Camden, Atlantic City, and Asbury Park, and sampled fare like cheesesteaks, salt water taffy, oysters, and deep-fried hot dogs.

The food trail was approved following a unanimous vote in January, and the trail was officially inaugurated last week. Among the stops included on the trail:

  1. Frank's Deli // Asbury Park
  1. Knife and Fork Inn // Atlantic City
  1. Dock's Oyster House // Atlantic City
  1. Tony's Baltimore Grill // Atlantic City
  1. James' Salt Water Taffy // Atlantic City
  1. Lucille's Country Cooking // Barnegat
  1. Tony & Ruth Steaks // Camden
  1. Donkey's Place // Camden
  2. Hiram's Roadstand // Fort Lee

The Reason Why 'Doritos Breath' Stopped Being a Problem

iStock/FotografiaBasica
iStock/FotografiaBasica

In the 1960s, Frito-Lay marketing executive Arch West returned from a family vacation in California singing the praises of toasted tortillas he had sampled at a roadside stop. In 1972, his discovery morphed into Doritos, a plain, crispy tortilla chip that was sprinkled with powdered gold in the form of nacho cheese flavoring.

Doritos enthusiasts were soon identifiable by the bright orange cheese coating that covered their fingers. But there was another giveaway that they had been snacking: a garlic-laden, oppressive odor emanating from their mouths. The socially stigmatizing condition became known as "Doritos breath." And while the snack still packs a potent post-mastication smell, it’s not nearly as severe as it was in the 1970s and 1980s. So what happened?

Like most consumer product companies, Frito-Lay regularly solicits the opinions of focus groups on how to improve their products. The company spent more than a decade compiling requests, which eventually boiled down to two recurring issues: Doritos fans wanted a cheesier taste, and they also wanted their breath to stop wilting flowers.

The latter complaint was not considered a pressing issue. Despite their pungent nature, Doritos were a $1.3 billion brand in the early 1990s, so clearly people were willing to risk interpersonal relationships after inhaling a bag. But in the course of formulating a cheesier taste—which the company eventually dubbed Nacho Cheesier Doritos—they found that it altered the impact of the garlic powder used in making the chip. Infused with the savory taste known as umami, the garlic powder was what gave Doritos their lingering stink. Tinkering with the garlic flavoring had the unintended—but very happy—consequence of significantly reducing the smell.

“It was not an objective at all,” Stephen Liguori, then-vice president of marketing at Frito-Lay, told the Associated Press in April 1992. “It turned out to be a pleasant side effect of the new and improved seasoning.”

Frito-Lay offered snack-sized bags of the new flavor and enlisted former heavyweight boxing champion George Foreman to promote it. Ever since, complaints of the scent of Doritos wafting from the maws of co-workers have been significantly reduced, and the Nacho Cheesier variation has remained the Doritos flavor of choice among consumers.

When Arch West died in 2011 at the age of 97, his family decided to sprinkle Doritos in his grave. They were plain. Not because of the smell, but because his daughter, Jana Hacker, believed that mourners wouldn’t want nacho cheese powder on their fingers.

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