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kottke.org posts about Oreo

The Fluid Dynamics of Oreo Cookie Twisting

Oreo cookies that have been twisted apart, with the creme sticking to one side of the cookie

You may have noticed, while twisting apart Oreos (aka the world’s favorite “trilayer laminate composite”) to get at the creme inside, that the creme tends to mostly stick to one half of the cookie. MIT graudate student Crystal Owens decided to study this phenomenon and has co-authored a paper about the failure mechanics of the Oreo’s layer of creme in the journal Physics of Fluid. From Ars Technica:

“I had in my mind that if you twist the Oreos perfectly, you should split the creme perfectly in the middle,” said Owens. “But what actually happens is the creme almost always comes off of one side.” The experiments showed that this creme distribution is not affected by rotation rate, the amount of creme filling, or the flavor. Rather, the pre-existing level of adhesion between the creme and the chocolate wafers seemed to be the determining factor. Cookies from the package within any one box typically separated with the same preferred orientation most of the time. This suggests that it has something to do with how the cookies are manufactured and then oriented during packaging, as well as how they are stored.

They even built a 3D printed “oreometer” so that people can study this phenomenon without using an expensive rheometer.

As a very amateur kitchen scientist myself, the Oreo situation reminds me of what happens when you try to tear three connected pieces of paper towel apart in one move by pulling on the outside pieces in opposite directions: the middle piece of paper towel almost always ends up attached to one of the outside pieces. In fact, in extensive testing over the past 3-4 years, this maneuver has only separated all three pieces a few times.1 (thx, eric)

  1. There’s always a lot of hootin’ and hollerin’ and victory laps around the kitchen when a perfect pull happens. It’s a rare event!โ†ฉ


The Oreo separator machine

And the TED Prize (“awarded to an extraordinary individual with a creative and bold vision to spark global change”) this year goes to this guy, who invented a machine for separating Oreos:

Congratulations! (thx, brad)


Chinese Oreos are tube-shaped

Well some of them are. The plain old American Oreo didn’t sell so well in China, so Kraft had to rethink everything about the cookie.

It turns out that if you didn’t grow up with Oreos and develop an emotional attachment to the cookie, it can be a weird-tasting little thing. And this started a whole process in the Chinese division of Kraft of rethinking what the essence of an Oreo really is.

Key terms in this article include “the essence of Oreoness” and “Twist, Lick, Dunk”.