Owens CE, Max R Fan, AJ Hart, GH McKinley (2022) On Oreology, the fracture and flow of “milk's favorite cookie®”.
Tests by rheometer
An Oreo is taken from the box and measured by gluing to the upper and lower plates of our laboratory rheometer. Delicate sensors report the torque required to twist the cookie open. Sadly, even with the best control, most of the creme ends up on one wafer (the lower one here).
In this video, more creme than normal actually remains attached to the upper wafer due to the heat generated from the lighting for the video! If you try it at home, the fracture surface should be much cleaner (at least 80% of the time or more).
Diagram of Oreo creme on our laboratory rheometer. The velocity profile is shown, where the base wafer is held in a fixed position while the upper wafer is rotated.
Tests by hand
If you take a freshly-opened pack of Oreos and twist the cookies by hand, you'll find that, most of the time, the creme will fall mostly onto one wafer rather than splitting between cookies. The one wafer will have a particular direction in the box -- for example, in this box the creme stuck best to the leftmost wafer.
This was true for cookies with different amounts of creme, with only a few showing creme splitting by ripping in half, forming half-moons on each wafer. Some wafers were broken.
Tests by hand were reproducible. But sometimes you may want to test more robustly, and not have access to a laboratory rheometer. What then?
Introducing the Oreometer
The animated Oreometer assembly video shows how to build the device once printed and use it to test an Oreo wafer. See the marking "RHEO" rather than "OREO" stamped on our cookie.
3D printing instructions
Guided tutorial on using the Oreometer
Behind the scenes in the Oreo factory: how the cookies are made. See 3:30-3:55 for how the creme and wafers are assembled.
From Futurama: suggested manufacturing method in which wafers are applied to the creme at the same time.
This study was in no way sponsored by Oreo or any food or snack company. When Oreo heard about it, this was their response.
One example of the fun broadcast coverage of Oreology
Other useful and interesting links about silly and serious snack science:
The history of cookies (podcast episode published April 2022): https://gastropod.com/the-way-the-cookie-crumbles/
Marshmallow peeps studies: http://www.peepresearch.org/
Profiles of Kansas vs the pancake - which is flatter?: https://www.usu.edu/geo/geomorph/kansas.html
Food models of the earth's lithosphere: https://www.annualreviews.org/doi/abs/10.1146/annurev.earth.36.031207.124326
How best to dip biscuits in tea (horizontally, not vertically): (long) https://www.nature.com/articles/17203
Vocabulary tutorial appropriate for 5-8th grade based on two of our articles, from MIT alum Faith Witryol https://docs.google.com/presentation/d/1i3fwraikgMryEFQw0c9qAADascJRHPcgQqTIuocwbLc/edit#slide=id.p