On Oreology, the fracture and flow of milk's favorite cookie®

The mechanical experience of consumption (i.e., feel, softness, and texture) of many foods is intrinsic to their enjoyable consumption, one example being the habit of twisting a sandwich cookie to reveal the cream. Scientifically, sandwich cookies present a paradigmatic model of parallel plate rheometry in which a fluid sample, the cream, is held between two parallel plates, the wafers. When the wafers are counter-rotated, the cream deforms, flows, and ultimately fractures, leading to separation of the cookie into two pieces. We introduce Oreology ((sic )), from the Nabisco Oreo for cookie and the Greek rheo logia for flow study, as the study of the flow and fracture of sandwich cookies. Using a laboratory rheometer, we measure failure mechanics of the eponymous Oreo's creme and probe the influence of rotation rate, amount of creme, and flavor on the stress-strain curve and postmortem creme distribution. The results typically show adhesive failure, in which nearly allw (95%) creme remains on one wafer after failure, and we ascribe this to the production process, as we confirm that the creme-heavy side is uniformly oriented within most of the boxes of Oreos. However, cookies in boxes stored under potentially adverse conditions (higher temperature and humidity) show cohesive failure resulting in the creme dividing between wafer halves after failure. Failure mechanics further classify the creme texture as mushy. Finally, we introduce and validate the design of an open-source, three-dimensionally printed Oreometer powered by rubber bands and coins for encouraging higher precision home studies to contribute new discoveries to this incipient field of study. (C) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0085362

Automated summary

This article introduces the study of Oreology, which focuses on the flow and fracture of sandwich cookies, using the example of the iconic Oreo cookie. The authors use a laboratory rheometer to measure the failure mechanics of the Oreo's creme and investigate the impact of rotation rate, creme amount, and flavor on the stress-strain curve and creme distribution. The results show adhesive failure under normal conditions, with the majority of the creme remaining on one wafer, but cohesive failure under adverse conditions, resulting in the creme dividing between wafer halves.