Research published in the journal Physical Review Fluids suggests optimal pancake cooking is all in the wrist – and demonstrates it with computational modelling.
The paper, written by E. Boujo & M. Sellier, seeks to demonstrate that liquids films on solid surfaces are subject to complex kinematics, all via the mechanisms of pancake making.
Challenged by Sellier’s wife to use physics expertise to suggest the optimal way to cook a crêpe, the two employed a tool called “optimal control theory”. This method allows you to incorporate how one quality of an object – say, pancake thickness – is dependent on another – say, frying pan motion. The model is quite complex, and incorporates factors which change throughout the cooking process, including how movement of the pan will affect the batter’s flow and thickness, how the layer of liquid in contact with the pan will solidify first, and the relation of this to its increasing viscosity throughout as it cooks.
Placing the parameters of the so-called perfect pancake as one which is ‘uniformly thin, hole-free, and perfectly circular’ – because, as Mythbusters taught us, the only difference between screwing around and science is writing it down – they note that the theoretical way to obtain these conditions isn’t possible under the realised conditions of pancake making. To the best of the author’s knowledge, modelling these types of flows had not been attempted before.
After detailing their parameters and solutions, they discuss the outcome of two modelling approaches. Interestingly, they conclude that one of the optimal methods identified by the more simplistic modelling approach appears to replicate the motion one would most likely naturally adopt when making crêpes. Thus, their scientifically-endorsed recommendation for perfect pancakes is as follows: first, tilt the pan to drain all the batter to one end, and then slowly rotate it for one or two revolution to distribute the batter over the remaining, uncovered pan surface.
The findings also have implications for applications within materials science, which may seek to coat surfaces evenly and efficiently via the use of gravity, and make an inspiring case for the effort to research and publish simple, engaging science. In particular food-based science is often particularly good at capturing our imagination, as we seek to understand the laws and rules that govern – or, help us justify – what we love. Human beings have been trying to find benefit in the consumption of wine since we started making it, with papyri from Egypt dating to 2200 BC including recipes for wine-based medicines. There’s even some evidence that chocolate might improve your memory, albeit only in frankly infeasible quantities.
The study of physics seeks to understand the rules governing matter, energy, and their interactions; while cooking can be chaotic at times, it is reassuring to know it is governed by fundamental laws, even crêpes!