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iStock // Lucy Quintanilla
iStock // Lucy Quintanilla

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.

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Chefs Launch World's Highest Pop-Up Restaurant at Mt. Everest Base Camp
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A touch of altitude sickness shouldn't stand in the way of a good meal. At least that seems to be the idea behind a plan to serve a seven-course dinner to trekkers at Everest Base Camp, the gateway for those planning to climb Mt. Everest in Nepal.

The four chefs leading this trip hope it will land them a new Guinness World Record for the highest pop-up restaurant on the planet, according to Architectural Digest. At the end of May, the chefs will take 10 people on an eight-day trek from the town of Lukla (at an altitude of about 10,000 feet) to Everest Base Camp (at 11,600 feet), all while foraging along the way for ingredients that can be incorporated into the meal. (For a true luxury experience, guests also have the option of traveling by helicopter.) The full package of flights, accommodations, and meals costs about $5600 per person.

After reaching their destination, trekkers will get to sit back and enjoy a feast, which will be served inside a tent to protect diners against the harsh Himalayan winds. Indian chef Sanjay Thakur and others on his team say they want to highlight the importance of sustainability, and the money they raise will be donated to local charities. Thakur said most of the food will be cooked sous vide, which allows vacuum-packed food to be cooked in water over a long period of time.

"The biggest challenge, of course, will be the altitude, which will affect everything," Thakur tells Fine Dining Lovers. "Flavor [perception] will be decreased, so we will be designing a menu of extraordinary dishes accordingly, where spices will have the upper hand."

This isn't the first time an elaborate meal will be served at Everest Base Camp, though. According to Fine Dining Lovers, another chef launched a pop-up at the same spot in 2016, but it presumably wasn't registered with the Guinness Book of World Records. Other extreme restaurants include one carved into a limestone cliff in China, one dangling 16 feet above the ground in a rainforest in Thailand, and one submerged 16 feet below sea level in the Maldives.

[h/t Architectural Digest]

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Do You 'Procrastibake'? You're Not Alone
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The urge to put off tasks until the last minute is often accompanied by a nagging sense of guilt about not being productive. A new trend tackles both problems at once. It's called procrastibaking.

As The New York Times reports, procrastibaking, or throwing yourself into a baking project to distract yourself from an impending work deadline, is popular among students, telecommuters, and anyone else with access to an oven and who needs a creative outlet divorced from their actual work. Preparing a difficult recipe with many steps may feel like a chore when you're making it for someone else, but when you're baking for baking's sake, the process becomes meditative. Procrastibakers often choose the most complicated recipes they can find: More time in the kitchen means less time spent thinking about their term paper (or bar exam, freelance gig, tax filing, etc.).

According to Google Trends, interest in the term procrastibaking first spiked in April 2010. The word gained momentum on university campuses. A writer named Gabrielle reports in a 2012 blog post for the online law student community Survive Law that procrastibaking and legal education go hand in hand, "because if you’re going to spend time away from the books, you may as well have something cool (and edible) to show for it." In 2014, the linguistics department at Monash University posted a blog detailing the connections between the word and the student tradition of bringing baked goods to meetings.

Today procrastibaking appeals to expert time-wasters of all ages and occupations. There are currently 26,585 posts with the hashtag #procrastibaking on Instagram—check them out if you need some inspiration for ways to push off your next project.

[h/t The New York Times]

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