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Fun fact: the torque required to twist an Oreo is about the same force you’d need to twist a doorknob.

Just like you, researchers at the Massachusetts Institute of Technology (MIT) want to know why more Oreo cream sticks to one of the wafers than the other when you twist the cookie apart. So, they put their brains together to conduct a series of tests to figure out what causes this cookie “fracturing.”

A bit of Oreo scouting may have led to the first clue. “Videos of the manufacturing process show that they put the first wafer down, then dispense a ball of cream onto that wafer before putting the second wafer on top,” Crystal Owens, a mechanical engineering Ph.D. candidate at MIT, who studies the properties of complex fluids, says in the release. “Apparently, that little time delay may make the cream stick better to the first wafer.”

Just one problem: which wafer is which? Thankfully, the team was paying attention when they pulled the cookies out of their boxes. The cream tended to stick to the inward-facing wafer, with cookies on the left side of the box landing the cream on the right wafer and cookies on the right sending the cream to the left wafer.

In the cookie-twisting research, published this week in the journal Physics of Fluids, the scientists used standard physics testing that looks at non-Newtonian flows (think: fluid not following Newton’s law of viscosity by changing viscosity when under force). They found that no matter the flavor—from the 1912-born classic cookie, to flavors such as birthday cake, mint, and so on—or the thickness of cream, the cream nearly always sticks to one wafer when twisted. Older boxes did show that the longer the cream ages, the more even the distribution, however.

The effort wasn’t about keeping all the snacks to themselves, though. The scientists created a 3D-printable “Oreometer” contraption that uses rubber bands and pennies to create the twisting force needed to fracture the sandwich cookie. It can also measure the rheology, or the amount of deformation, that Oreos and other sandwich cookies experience in the process. (You can find open-source 3D printer files for the machine here.)

The lab’s rheometer—basically an MIT-level Oreometer—featured sensors tracking the data with Oreos glued to the device’s plates. With changing degrees of torque and angular rotation, the team measured Oreo cream viscoelasticity, known as “flowability,” and where that cream landed at the end. After 20 boxes of Mega Stuf, dark chocolate, golden wafer, and more, the Oreo cream stood resolute.

“We had expected an effect based on size,” Owens says. “If there was more cream between layers, it should be easier to deform. But that’s not actually the case.”

While studying the twisting motion, the engineers also discovered the torque required to successfully open an Oreo is about the same as what’s needed to turn a doorknob—a tenth of the torque required to open a bottle cap. And if you want to get that cream to budge, know that it holds in place twice as well as cream cheese and peanut butter, more in line with the sticking power of mozzarella cheese, the MIT group found.

Owens believes this research could help us better understand 3D-printed fluids, but it definitely didn’t help come up with a solution for getting an even spread of cream across Oreo wafers. “As they are now,” she says, “we found there’s no trick to twisting that would split the cream evenly.”