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“Oreology” investigates mystery of why Oreo creme filling usually sticks to one side

MIT team also designed 3D-printed DIY rheometer for at-home or classroom experiments.

If you have to test the mechanics of an Oreo, what better fixture is there than an oreometer?

Everyone has their preferred method for snacking on tasty Oreo cookies: twisting the two halves apart to eat the creme filling first, perhaps, before dunking the chocolate wafers in a glass of milk. But you may have noticed that the creme typically sticks to only one chocolate wafer. MIT scientists tried to get to the bottom of why this is so often the case in a paper published in the journal Physics of Fluids. The authors playfully invoked a new scientific subfield they dubbed "oreology" ("Oreo" after the classic Nabisco cookie, "logy" from the Greek for "flow study," rheo logia).

Co-author Crystal Owens, a graduate student at MIT, doesn't study foods in particular; her primary focus is on 3D printing with complex fluid inks. "But great examples of complex fluids are all around us—many foods, sauces, condiments, yogurt, ice cream, and other products," she told Ars. "So it's natural and convenient to find foods to test our theories." Early on in her Phd thesis research, Owens designed a novel rheology tool and tested it on hair gel and mayonnaise to make sure it would work with everyday materials.

There is rich scientific literature on what Owens calls "kitchen relevant flows." For example, scientists have studied the structure of cheese; investigated the composition and flow of gluten-free batter and breads; discovered why strands of honey can get so long and thin as they drip without actually breaking; figured out a way to get cocoa butter to distribute more evenly in chocolate to enhance the perceived texture; studied why Brazil nuts rise to the top of a can of mixed nuts (aka the "Brazil nut effect"); and figured out how to "tune" the flow of Swiss cheese fondue by adding cornflour or wine.