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.

See Which Ingredients Cooks From Around the World Love Most

iStock
iStock

Food is incredibly regionally specific, and cuisines have been refined over millennia based on what ingredients have been available and what local cooks have come up with. Even though global trade has made the same spices and other flavor staples available virtually anywhere in the world, Mexican food still tastes radically different from Chinese food, and Italian food from Irish food. We know this intuitively—few of us pick up a bottle of soy sauce thinking we’ll use it in a traditional Italian pasta dish—but it’s still fascinating to see a breakdown of just which ingredients certain cuisines have cornered the market on, as you can in these charts.

Nathan Yau of FlowingData visualized the most-used ingredients in 20 different cuisines, using data on ingredients from Yummly to figure out what distinct flavors and ingredients country-specific cuisines gravitate towards.

Across the world, salt is king. It’s the most-used ingredient in 75 percent of the cuisines Yau looked at, and the only cuisine in which it doesn’t appear in the top five most-used ingredients is Korean food—but, like in other Asian cuisines, Korean recipes use soy sauce more than any other ingredient, and that in itself is very salty.

Because so many cuisines rely heavily on the same ingredients, like soy sauce and salt, Yau also calculated the ingredients most specific to each cuisine: the ones disproportionately used in one country’s traditional cuisine. This is where you start to get a picture of the kind of ingredients we associate heavily with particular regionally specific dishes. Mexican food relies on tortillas; Greek food, feta cheese; Korean, kimchi; Thai, lemongrass; Russian, beets; and Cajun, andouille sausage. Some ingredients may come as a bit of a surprise, though. Southern cooking in the U.S. uses vanilla extract more than other cuisines do, and the French love shallots. Cajun cooks are big fans of celery ribs, and somehow, though numerous cuisines use onions heavily, Brazilian cooks use them slightly more than anyone else.

The data relies on Yummly recipes, so the results are limited to what the recipe recommendation site has available. It's possible that home cooks working in each cuisine do something slightly different that might move the data in another direction. But, since Yummly currently has more than 2 million recipes available, it seems like a relatively large snapshot of cooking options.

Explore the interactive graphic and learn more at FlowingData.

15 Behind-the-Scenes Secrets of The Great British Baking Show

Netflix
Netflix

by Sarah Dobbs

If you’re an American fan of The Great British Bake Off you probably know it better as The Great British Baking Show (though its most devoted fans simply call it GBBO, which saves a lot of time). While its ninth season just kicked off on England’s Channel 4, American audiences are only now just getting caught up on season eight via Netflix. And with new hosts Noel Fielding and Sandi Toksvig taking over for Mel Giedroyc and Sue Perkins, plus Prue Leith taking over for Mary Berry as host, the latest incarnation of the show looks a lot different.

A bona fide global sensation, the baking competition has the power to cause otherwise rational human beings to immediately run to their nearest supermarket in search of obscure ingredients like psyllium or Amarula cream liqueur. It’s a charming, retro, warming hug of a TV show. But how much do you know about what goes on behind the scenes? Without destroying any of your illusions, here are some secrets about how the producers whip up one of the world's most beloved cooking shows.

1. THE REASON WHY IT HAS TWO DIFFERENT NAMES IS SIMPLE.

A scene from The Great British Bake Off
Netflix

If you’ve ever wondered why the series is called The Great British Bake Off in England and The Great British Baking Show in America, the answer is simple: Pillsbury. The Pillsbury Bake Off, which kicked off in 1949, is probably America’s most famous baking contest. And the company didn’t want there to be any confusion among viewers, hence The Great British Baking Show.

2. THE OVENS ALL HAVE TO BE TESTED EVERY DAY.

It’s difficult enough to make a cake that Paul Hollywood won’t declare either under- or over-baked without having to worry about whether your oven is working properly. So for every day of filming, every oven has to be tested. And because this is a baking show, they’re tested with cakes. Yes, every day every oven has a Victoria sponge cake cooked in it, to make sure everything’s working exactly as it should be.

3. EVERY TIME SOMEONE OPENS AN OVEN DOOR, THERE'S A CAMERA WATCHING THEM.

To make sure they catch all the drama, GBBO producers insist that every time a bake is put into or taken out of an oven, the moment must be caught on camera. So whenever a baker wants to put their goodies into an oven, or check if they’re ready to come out, they need to grab someone to make sure the moment gets captured on film. (Which must be a hassle for the first couple of weeks, when there are more than 10 bakers all trying their best to produce a perfect bake at once.)

4. THE CONTESTANTS HAVE TO WEAR THE SAME CLOTHES ALL WEEKEND.

It’s a minor thing, but have you ever noticed that the bakers wear the same clothes for an entire episode, even though it’s shot over two days? For continuity purposes, the contestants are asked to wear the same outfits for the entire weekend. If you’re the kind of baker who ends up with flour all over your shirt whenever you bake up a loaf of bread, the second day of filming could be a bit of a nightmare.

"Luckily they change the aprons so we don't look like a Jackson Pollock painting by the end of it," 2013 champion Frances Quinn told Cosmopolitan. "I think layers [is the answer], but even then you still have to wear what you had on, on top. Difficult."

5. THE CONTESTANTS DON’T HAVE A LOT OF DOWNTIME.

Having any time to spare is not something that season seven contestant Jane Beedle remembers happening regularly for the contestants. "Maybe once or twice, and when they did we would just sit and have a cup of tea and chat with the people around us,” she told the Mirror. "They don't like it if you have nothing to do, so they try and make the challenges as difficult as possible to keep you busy."

6. THE TEMPERATURE IN THE TENT CAN MAKE OR BREAK A BAKE.

Sue Perkins, Mary Berry, Paul Hollywood, and Frances Quinn in 'The Great British Bake Off'
BBC

Forget setting the oven to the correct temperature—the temperature inside the tent is just as important to a bake. "It's completely alien to your own kitchen at home,” Quinn told Cosmopolitan. “The temperature fluctuates—you'd be making a meringue and it would start raining, or we'd try and make pastry and it would be 27 degrees outside. The technical challenges and lack of time and lack of fridge and work space are the enemy on that show."

7. THE ILLUSTRATIONS ARE CREATED BY TOM HOVEY, AFTER THE EPISODE HAS FILMED.

You know those fun illustrations of the confections that pop up when each baker explains what they’re going to make that day? Those are all drawn by illustrator Tom Hovey. He was working as a video editor on the first season of GBBO when the producers realized they needed an extra visual element—so he offered his illustration skills. And while we see the illustrations on screen before the bakers attempt to make them a reality, Hovey told the BBC he draws them “a pack of photos of the finished bakes from the set after each episode has been filmed … I sketch out all the bakes quickly in pencil to get the details, form and shape I am after. I then work these up by hand drawing them all in ink, then they’re scanned and colored digitally, and then I add the titles and ingredient arrows. It's a fairly well streamlined process now.”

Even if a bake goes horribly wrong, Hovey said his “illustrations are a representation of what the bakers hope to create. Even if the bakers don't produce what they’ve intended to I have a degree of artistic license to make them look good.”

8. THE CONTESTANTS DON’T INTERACT WITH THE JUDGES VERY MUCH.

“They very much tried to keep it unbiased,” Quinn said about how the bakers don’t spend much time interacting with the judges. “We saw a lot more of Mel and Sue. Mary and Paul would purely come in to do what we called the royal tour—where they'd come in and find out what you were making, and then they'd come back in for judging. You're not in the same hotel having sleepovers! You form more of a relationship after the show when you see them at things like BBC Good Food or whatever—but they need to keep their distance [on the show]. They're there as judges."

9. MAKING SURE THAT THE TECHNICAL CHALLENGE IS ACTUALLY POSSIBLE IS ONE PERSON'S JOB.

Sandi Toksvig in 'The Great British Bake Off'
Netflix

Another vital behind-the-scenes role is that of the food researcher. It’s down to them to make sure that the elaborate concoction the judges have decided the bakers have to whip up is actually possible, given the ingredients, instructions, and time the bakers will be allowed.

The tent presents its own challenges, too, because it could be hot or cold, depending on the weather, and it tends to have quite a wobbly floor, which can make delicate decorating work trickier than it might otherwise seem. “The tent is just mocked up, so the floor is really bumpy and bouncy because you’d got so many camera guys running around,” Quinn told the Irish Examiner.

10. THE SHOW GOT INTO SOME TROUBLE FOR ITS PARTNERSHIP WITH SMEG.

Part of GBBO’s homey charm has to do with the setup of the tent where the bakers do their cooking, and few appliances spell “retro” as well as a colorful Smeg refrigerator. A viewer fed up with what they described as “blatant product promotion” wrote to the Radio Times to complain, and an investigation was launched into the series’ agreement with Smeg. As BBC guidelines state that a series may "not accept free or reduced cost products" in return for "on-air or online credits, links or off-air marketing,” the broadcaster ended up having to write the company a check for all the times their product got some screen time.

11. THERE ARE NEVER ANY LEFTOVERS.

The judges only take a mouthful of every bake, which seems to leave an awful lot of leftover pastries, cakes, and ridiculously complicated bread sculptures. But don’t worry—none of it goes to waste. “The crew eats all the leftovers," Beedle told The Mirror. "We get some brought to us in the green room so we can taste each other's bakes, but it's only slithers."

12. HUNDREDS OF SEASON FIVE VIEWERS WROTE IN TO COMPLAIN ABOUT “SABOTAGE.”

Midway through season five, contestant Iain Watters had a bit of an issue with his Baked Alaska. Realizing that his ice cream had not yet set, he threw the entire dish into the trash rather than serve the judges a subpar dessert and was sent home as a result. Footage from the episode made is seem as if fellow contestant Diana Beard had removed his ice cream from the freezer. Beard left the show at just about the same time due to health issues, but some viewers (811, to be exact) smelled sabotage—and wrote in to the show’s producers to complain. Media watchdog group Ofcom looked into the matter, but said that they had assessed viewers’ complaints and “they do not raise issues warranting further investigation under Ofcom’s rules.”

Paul Hollywood took to Twitter to clear up what became known as “bingate,” tweeting: “Ice cream being left out of fridge last night for 40 seconds did not destroy Iain’s chances in the bake off, what did was his decision BIN.”

13. MARY BERRY WATCHED BREAKING BAD BACKSTAGE.

Although it looks pretty nonstop on screen, there’s quite a bit of downtime during the show’s filming days. Especially for the show’s judges and hosts. Former judge Mary Berry had one unique way of passing the time: binge-watching Breaking Bad. “It’s shocking,” Berry told The Telegraph. “Then you get into it and you think: ‘Have I seen episode four or five?’ You get hooked. It’s better than motor racing, which [my husband] Paul watches—though I’d prefer Downton Abbey.” She’d apparently rope former hosts Mel and Sue into watching it with her on occasion. What better way to relax during a long day of baking than by watching Walter White, umm, baking?

14. THE APPLICATION FORM IS NO JOKE.

Fancy your chances in the Bake Off tent? If you’ve been inspired by the show and reckon you could nab a couple of Star Baker titles, brace yourself: The application form is a whopping eight pages long, and it’s full of probing questions. As well as giving details of your hobbies, lifestyle, and level of experience with various types of baked goods, it also asks applicants to describe their baking style, and answer a couple of existential-sounding questions.

"It's a long application form. I think it's designed to put some people off, essentially," fourth season contestant Beca Lyne-Pirkis said. "It asks you about everything you have done, good and bad. It's designed to get information about your character, stories, mishaps and successes."

Still fancy applying? Though submissions are not open at the moment, you can keep your eyes open for when the next batch of contestants are being accepted here.

15. THE AUDITION PROCESS IS EVEN MORE GRUELING.

If you happen to make it through the application process, the audition process is even more difficult. “Every person who makes it into the marquee has passed a rigorous series of tests,” GBBO creator and executive producer Anna Beattie told The Telegraph. In addition to the application form, The Telegraph reported that there is “a 45-minute telephone call with a researcher, bringing two bakes to an audition in London, a screen test and an interview with a producer. If they get through that, there is a second audition baking two recipes … in front of the cameras, and an interview with the show psychologist to make sure they can cope with being filmed for up to 16 hours a day.”

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