Egg slide rule
The one kitchen utensil you did not yet own...
The physicist Charles Williams of Exeter University has a published formula[1] that solves an old problem: how long should you boil an egg.
The formula looks like this:
The formula assumes that the water is already boiling before the egg is put into the water, and that the process takes place at an air pressure of 1 atmosphere.
The following constants apply:[3]
It is not easy to use this formula in the kitchen. A slide rule would be a great help. However, I have never seen an egg boiling slide rule, not even in the patent literature.
Therefore I offer here my own design of an egg slide rule:[4]
Move the arrow of the Tegg-slide to the weight, choose the Tegg-scale corresponding to your taste, locate the initial temperature of the egg and read the cooking time above this temperature value. For convenience, standard refrigerator temperature * and room temperature [] are highlighted on the Tegg-scale. The EU standard weight classes[5] are indicated below the weight scale.
In the derivation of the formula several approximations are used, like the egg being spherical, and not cooking at a high altitude.
So use the results with a pinch of salt.
Do you want to see a
real-life egg slide rule?
Thomas Kirchhof made one.
Notes
Charles D.H. Williams, "The Science of Boiling an Egg".
H. de Lang, "Molecular gastronomy", Nederlands Tijdschrift voor Natuurkunde [Dutch Journal of Physics], 7412 (2008) page 431–433.
S. L. Polley, P. O. Snyder, P. Kotnour, Food Technol., 3411 (1980) page 76–94.
Download a higher resolution PDF version of this slide rule.
Regulation (EC) No 589/2008 of the Commission of 23 June 2008 laying down detailed rules for implementing Council Regulation (EC) No 1234/2007 regarding marketing standards for eggs.