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.

7 Bizarre Lawsuits Involving McDonald's

McDonald's can sometimes offer up a side of litigation.
McDonald's can sometimes offer up a side of litigation.
Yu Chun Christopher Wong, S3studio/Getty Images

Since the 1950s, McDonald’s has been serving up a menu full of convenient, fast-service food, from their signature Big Mac to the portable Chicken McNugget. Unfortunately, not everyone has been happy with their Happy Meals. The company has occasionally found itself embroiled in complaints from customers who have been dissatisfied and requested a side order of litigation. Take a look at some of the legal cases tossed around the Golden Arches over the years.

1. McDonald’s v. Ronald McDonald

A photo of Ronald McDonald outside of a McDonald's in Thailand
McDonald's mascot Ronald McDonald.
PhonlamaiPhoto/iStock via Getty Images

The ability for McDonald’s to find itself in the middle of legal quandaries was demonstrated early on. After being in business for 14 years, the independently-owned McDonald’s Family Restaurant in Fairbury, Illinois, was issued a legal notice from the McDonald’s corporation in 1970 warning them to avoid using any arches or offering drive-in service. The letters continued for decades, with owner Ronald McDonald (yes, that is his real name) paying little attention. It was, after all, his family’s name and restaurant. But McDonald’s upped the ante in 1992, when a local franchisee finally opened a mile down the road, and a flurry of activity commenced. McDonald (the person) eventually settled, and the two locations became known to locals as McDonald’s East and McDonald’s West. The agreement also required Ron to take the possessive “S” off the family restaurant name, but it went back up in 1996, when the franchise location closed.

2. The Quarter Pounder Controversy

The McDonald’s Quarter Pounder seemingly leaves little to the imagination. It promises one quarter-pound of meat, which it delivers. (You can also opt for the Double Quarter Pounder, which gets you closer to an entire cow.) It also comes with cheese, which caused some strife at a South Florida location in 2018. Two customers, Cynthia Kissner and Leonard Werner, filed a $5 million class action lawsuit in Fort Lauderdale because the restaurant charged them the full price of a Quarter Pounder despite their request for employees to hold the cheese. The plaintiffs argued that the McDonald’s app offered a Quarter Pounder without cheese for roughly 30 cents less and that they should not have been charged more when they asked to hold the cheese. Not all locations, however, offer that option, and the argument that the cheese and no-cheese burgers are somehow one product was not convincing to the judge. As the customers were unable to prove damages, the case was thrown out of court.

3. H.R. Pufnstuf Invades McDonaldland

H.R. Pufnstuf attends "Sid & Marty Kroft's Saturday Morning Hits" DVD release party at Every Picture Tells A Story on November 20, 2010 in Santa Monica, California
H.R. Pufnstuf attends "Sid & Marty Kroft's Saturday Morning Hits" DVD release party.
John M. Heller/Getty Images

McDonaldland, that child oasis found in many McDonald’s commercials of the 1970s and featuring a variety of characters from the Hamburglar to Grimace, was once the subject of a legal struggle. Sid and Marty Krofft, producers of the psychedelic kid’s series H.R. Pufnstuf, sued McDonald’s alleging that Mayor McCheese was copied from its own political abomination, Pufnstuf. (Both have enormous heads, and Pufnstuf was mayor of Living Island.) The Kroffts claimed that Needham, Harper & Steers, the ad agency responsible for McDonaldland, consulted with them before breaking ties and producing the commercials on their own. The courts ruled in favor of the Kroffts in 1977, declaring the ads took the “total concept and feel” of the Kroffts’ show. McDonald’s was ordered to pay $1 million and had to stop airing the ads.

4. The contaminated Coca-Cola

In 2016, Trevor Walker ordered a Diet Coke from a Mickey D's in Riverton, Utah. While lower in calories, it was apparently higher in illegal substances. The drink was somehow contaminated with Suboxone, a heroin substitute. Walker temporarily lost feeling in his arms and legs and had to be taken to the emergency room of a local hospital. Walker sued, but McDonald’s argued they should be dropped from the lawsuit owing to the fact that they are removed from the day-to-day operations of franchised locations. (A manager and employee were suspected of spiking the drink, but security footage was unavailable to confirm the theory.) Third District Court Judge James Gardner was unmoved, saying McDonald’s couldn’t be that separated if they also mandated franchise managers attend Hamburger University for training—or “this hamburger school,” as Gardner put it. The case is ongoing.

5. Big Macs and brothels

In 2012, former McDonald’s employee Shelley Lynn sued McDonald’s and made the audacious claim that the company’s low wages had forced her into a side job as a prostitute for a Nevada brothel. Lynn was hired for a position at an Arroyo Grande, California, McDonald's location, where she alleged manager Keith Handley pushed her into a life of sex work. Lynn complained there was no practical grievance system in place and that Handley should not have been sold a franchise. A United States District Court judge in California found in favor of McDonald’s and Handley that same year.

6. McDonald's In a Pickle

A double hamburger is seen on July 18, 2002 at a Burger King in Miami, Florida.
Joe Raedle/Getty Images

In 1999, Veronica Martin and her husband ordered hamburgers from a McDonald’s in Knoxville, Tennessee. What should have been a delicious treat turned ugly as—according to Martin—a very hot pickle shot out from between the bun, landed on her chin, and scalded her, leaving her with second-degree burns. A lawsuit followed, with Martin arguing the pickle was “defective.” She sought $110,000 while her husband asked for $15,000 for losing the “service and consortium” of his wife. The two parties settled in 2001, though McDonald’s maintained no monetary payment was offered.

7. a Weighty Problem

It can be assured that excess consumption of calories, whether they come from McDonald’s or other sources, will result in an accumulation of fatty tissue. This did not prevent several overweight teenagers in New York from taking McDonald’s to court in 2002 in an attempt to place responsibility for their habit of eating at McDonald’s several times a week at the feet of the corporation. The plaintiffs, Ashley Pelman, 14, and Jazlyn Bradley, 19, among others, said they did not know how fattening the food was and complained of high blood pressure and high cholesterol, among other ailments. One plaintiff, a 600-pound 15-year-old, said he ate there every day. Lawyers argued advertising to children helped foster a trust of the food’s nutritional value.

The case was rejected by a judge in 2003. Now at least 26 states have “common sense consumption” laws, which prevent lawsuits from being filed against food manufacturers for adverse health effects as a result of gorging on a decadent diet. It's also known as the "cheeseburger law."

A Friends-Themed Brunch Is Coming to Los Angeles

The friends brunching in Las Vegas after Ross and Rachel impulsively tied the knot.
The friends brunching in Las Vegas after Ross and Rachel impulsively tied the knot.
NBC

Whether they were sampling Monica’s latest culinary creation, ordering yet another pizza, or eating cheesecake off the hallway floor, the legendary friends of Friends definitely spent a lot of time appreciating food—and coffee, of course.

To give fans a chance to celebrate those central motifs, The Brunch Club is hosting a Friends-themed brunch in Los Angeles this spring. Attendees will get to enjoy mimosas and appetizers during a screening of quintessential Friends episodes. The event also promises an array of activities including trivia, charades, and a costume contest. (So if your closet happens to be harboring an armadillo getup or a pink, frilly bridesmaid dress inspired by Little Bo-Peep, now’s the time to dig it out.)

friends-themed brunch
There won't be beef in the trifle at this Friends-themed brunch.
The Brunch Club

Though the exact location hasn’t been announced yet, we know the brunch will take place from 12 p.m. to 2 p.m. on Sunday, May 17, and you can register on Eventbrite to receive an email update when tickets go on sale. The price isn’t listed, but there’s a similar Friends brunch happening in Denver this March, and those tickets cost around $50.

The Brunch Club specializes in raising a glass to pop culture phenomenons all over the country—according to the website, the organization has hosted brunches inspired by the Spice Girls, Drake, roller discos, and more. Considering that the entire Friends series left Netflix at the end of 2019, the news of a fun way to watch a few episodes is probably coming at a good time for devastated super fans in Los Angeles.

In the meantime, here’s what we know about the potential Friends reunion.

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