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.

8 Surprising Uses for Potatoes

istock
istock

Potatoes are one of the world’s most common, and most beloved, vegetables—and they can be used for much more than just sustenance. In honor of National Potato Day, here are a few other ways to use a potato.

1. WEAR THEM

Potatoes come from a nightshade plant called Solanum tuberosum, which blooms with white, pink, red, blue, or purple flowers. In the late 1700s, in an effort to inspire their starving subjects to plant the newly introduced vegetable—which the Spanish had brought to Europe from the New World—Marie Antoinette wore potato flowers in her hair, and her husband King Louis XVI wore them in his buttonholes. This inspired potato flowers to be a favorite of the French nobility for a time, but the ploy didn't work: The lower classes spurned the upper class's efforts to get them to farm the crop. 

2. MAKE ELECTRICITY

If you’re in a lurch, or perhaps a doomsday prepper, start stocking up on potatoes now. With just a few household items—wires, some copper, and a zinc-coated nail—and one of the tubers, you can power a clock, a light bulb, and many other small electronics.

3. GARDEN IN SPACE

In 1995, the potato became the first vegetable grown on the space shuttle. Raymond Bula of the University of Wisconsin spearheaded a project in which five Norland variety potato leaves were propagated in space. Bula’s research group monitored this project from Wisconsin, staying in constant contact with NASA, who stayed in contact with the crew on the space shuttle. When the shuttle arrived home, everyone was pleased to find that the potato plants not only survived the ordeal, but actually grew potatoes.

4. GROW ROSES

Gardeners can insert rose cuttings into a potato, and then plant the entire potato as if it were a seed or bulb. The nutrient-rich potato helps provide moisture and sustenance to the growing plant, giving the cutting a better chance to survive.

5. MAKE PLASTIC

Bio-plastics, as they’re called, can be made from corn, wheat, and—you guessed it—potatoes. The concentration of starches and cellulose in a potato can be used to make plastic, and the plastic made out of potatoes can be burned and composted with much less impact on the environment.

6. MEASURE TIME

Peru’s Incas used the potato for all sorts of things at the height of their civilization. Known for creative, forward-thinking agricultural practices, the Incas also studied time—and started using the time it takes to cook a potato to measure time.

7. REMOVE RUST

Have a knife with some rust spots? If you insert the knife into the potato and let it sit for awhile, you'll go a long way in removing the rust. Potatoes naturally contain oxalic acid, which is used in many household cleaning products (in much greater quantities, of course). Oxalic acid also dissolves rust. To attack larger rusted surfaces with a potato, cut it in half, sprinkle baking powder on it or dip it in dish soap, and get to scrubbing.

8. MAIL THEM

Thanks to Mail A Spud, for only $9.99 everyone’s dream of mailing a potato to their closest friends and family can be a reality. The site advertises that it can send potatoes anywhere in the U.S., and that your choice of mailed gift will be sure to delight recipients. And, if not delight, at least confuse ... in a good way.

Additional Sources: Potato: A History of the Propitious Esculent

This article originally ran in 2016.

Which Kind of Oatmeal is Best for Your Health?

iStock
iStock

Like a lot of nutritionally robust foods, oatmeal sometimes gets a bad rap for being boring. Even the sight of plain, cooked oats—often resembling a mushy kind of paste—can have people passing it up in favor of a sugary cereal or pancake stack. But oatmeal can wind up being one of the better breakfast choices, not only in taste, but also in its health benefits, Time reports. It all comes down to what type of oatmeal you buy and how you prepare it.

To determine your best oat option, it helps to understand that oatmeal isn’t really oatmeal. When oats are harvested, they’re wrapped in a hard husk that manufacturers remove to facilitate cooking. Inside is the groat, a complete grain full of fiber. When you buy oatmeal that’s labeled “instant,” "quick-cooking," "rolled," or "old-fashioned," the groat has been steamed and rolled flat to make it easier to cook. The mostly unadulterated oatmeal labeled “steel-cut” or “Irish” is actually made up of groats that have been chopped up but are otherwise whole.

Typically, the faster you can cook the oatmeal, the more it’s been processed and the less it resembles the groat from the field. Because they resemble kernels and remain thick, steel-cut oatmeal requires the longest preparation, simmering on a stovetop for 30 minutes or so. Processed oats are flaky and can easily be heated.

Nutritionally, both rolled and steel-cut oats have the same profile. Both are fibrous and high in vitamins E, B1, and B12. Steel-cut oats have a heartier texture, while instant tends to take on a loose, light consistency. But because steel-cut oatmeal keeps more of the whole grain intact, it tends to be higher in fiber and lower on the glycemic index and provides more of a slow-burn energy as opposed to the quick burst of the sugar found in flavored instant oatmeal packets.

If you want to opt for steel-cut oats but are short on time, there are solutions. You can soak oats overnight to reduce cooking time down to 10 minutes or so on the stove, or prepare a week’s worth so you can quickly re-heat portions. Topped with yogurt, peanut butter, or fruit, it’s one of the best breakfast choices you can make. And with a little foresight, you won’t have to sacrifice your busy morning to enjoy it.

[h/t Time]

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