Food Science

How Long to Dunk an Oreo, According to Science

August 11, 2017

There’s a delightful new piece up at Mental Floss that goes into great detail about a quietly vexing conundrum: How long should you dunk an Oreo in milk? The answer, writer Lucas Reilly found, is three seconds.

Here’s a concern some may not believe could possibly be a matter of scientific inquiry. There’s a careful choreography involved in dunking an Oreo, that wondrous disc of compressed sugar, into milk. Blot it for a mere second and you may as well have eaten it dry. Soak it for too long and it’ll collapse into pieces, demanding you fish it out of your milk with a utensil. Estimating the correct time, one that'll stimulate a beautiful collapse of a biscuit and its cream contents without transmogrifying its texture too violently, is a difficult art to master.

Reilly is recycling the contents of a study conducted last year by researchers at Utah State’s Splash Lab. They took Oreos, Chips Ahoy!, Nutter Butter, and Graham Crackers, and dipped them in tubs of 2% milk from half a second to seven seconds. Across this spectrum, researchers measured how much milk these cookies had absorbed.

The team at Splash Lab was building on a body of scientific inquiry that began in 1999, when then-University of Bristol physics professor Len Fisher discovered how capillary action—the way liquid molecules stick to solid surfaces—could explain the best amount of time to dunk a British biscuit. To explain why a cookie—essentially a collection of “small, starchy tubes”—is catnip for milk, he worked off of a formula devised by American scientist E.W. Washburn, and, through it, determined that three and a half-to-five seconds was optimal for a British biscuit.

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The Oreo’s a different animal, though; so this realization compelled the Splash Lab to build on Fisher’s findings and apply them to mass-market American cookies. (After all, dunking Oreos in milk is something of a national pastime.) In the experiment, Oreos absorbed half of their potential liquid weight at a mere second. By two seconds, they absorbed 80%, flatlining for the third second; at the fourth, they finally absorbed all possible milk.

For reference, the Nutter Butter followed the same trajectory as the Oreo, a fact that's totally unsurprising, given its compositional similarity to the Oreo. Chips Ahoy! cookies absorbed roughly 45% of their liquid weight within half a second, plateauing at 85% after one second until the fifth, after which it absorbed all its liquid weight. Graham Crackers, those feeble foodstuffs, absorbed all of their liquid weight at the one-second mark.

This three-second rule isn’t ironclad for all milks. The more butterfat-rich your milk is, the longer you can dunk, and the more these milks coax the flavor out of the cookies—enhancing, rather than eroding, their flavor profile. Reilly recommends a cocktail of whole milk and half-and-half—or, even more brazenly, heavy cream—if you’d like to prolong that pleasure by a few seconds.

I’ll stick to the 2% and the three-second milk rule. Optimal indeed.

Got an opinion on this wildly important scientific matter? Please let us know in the comments.

See what other Food52 readers are saying.

  • M
  • Greenstuff
  • piotro
Mayukh Sen is a James Beard Award-winning food and culture writer in New York. His writing has appeared in the New York Times, the New Yorker, Bon Appetit, and elsewhere. He won a 2018 James Beard Award in Journalism for his profile of Princess Pamela published on Food52.


M August 12, 2017
I think Utah State needs to find something better to be spending their research funds on... I know this is just trying to be a bit fun and tongue and cheek, but my husband is a medical research scientist and he fights nail and tooth for money to help people, and money is being spent on cookie research?! A bit hard to swallow (no pun intended).
piotro August 14, 2017
I feel ya, but I'm sure the funding came from the cookie companies themselves in this instance!
Greenstuff August 11, 2017
Let me just put it out there that we ate Oreos in the '50s and '60s so that you wouldn't have to. Please, children, listen to Elvis and the Beatles, but reject us boomers when it comes to what you dunk! You CAN do better.