Rather unusual and frankly not essential, the science of Oreo or “Oreology” is a particular field of research that uses fluid mechanics to better understand how humanity tastes these famous black and white cookies.
An ideal complex fluid
In the many scientific journals, the publications concern a untold number of disciplines. Sometimes, certain fields of research are quite outlandish, such as that of a team of researchers from the Department of Mechanical Engineering at the Massachusetts Institute of Technology (MIT). Their publication in the journal Physics of Fluids January 15, 2022 details the Oreology or rather the science of the Oreo. The goal? Understand the reasons why the white cream remains stuck to one of the two parts while completely detaching from the other when the biscuit is separated in two. According to the researchers, the cream is a ideal complex fluid to test their theory.
Crystal Owens, one of the study participants, spoke in an article published by Ars Technica where she explains that eating a cookie with cream tastes different than eating the two cookies together. At first glance, it may seem quite difficult to define the relationship to science, but according to the researcher, it is a question of rheology here. This discipline is none other than the study of the deformation and flow of matter under the effect of the application of a stress.
A invalidated starting theory
Rheology requires the use of very specific test machines (rheometers). However, the Oreo cookie seems to embody a typical example of the ” parallel plate rheometry“. Concretely, this machine has two discs squeezing a fluid through reverse twists in order to test its reactions. In the case of the Oreo, the two cookies embody the trays and the cream, the fluid. For the purposes of the study, the scientists therefore bought classic Oreo cookies, but also variations in several versions possibly having different properties. Then, they tried to verify the following theory: by twisting the Oreo in a perfect way, it is possible to properly distribute the cream between the two biscuits during the separation.
Using a specially 3D-printed device (oreometer), the researchers finally invalidated the theory. They stuck the two cookies together using glue on two rotating trays. However, no matter the rotation speed or the variety of the Oreo, the cream remained almost invariably stuck to one of the walls. For scientists, this behavior is the result of the way these cookies are made in the factory. The study concluded that the cream of the famous biscuit combined the breaking qualities of certain Parmesan-type cheeses and the deforming qualities of mozzarella.
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