We’ve all heard that favorite summer colloquialism: “It’s so hot you could cook an egg on the sidewalk!” During some of these August days that certainly seems possible, but have you ever tested the theory? Can you really cook an egg on the sidewalk? Is concrete able to conduct enough heat? What about asphalt? We’re here to answer these hard-hitting questions.
In order for an egg to cook and become firm, proteins in the egg must modify and then coagulate, and this can only happen at 158°F or higher. The question then becomes: Can a concrete sidewalk reach that temperature? Unfortunately, the answer seems to be a myth-shattering “no.” Temperatures can vary depending on the composition of the concrete, the directness of the sunlight and, of course, the air temperature. Arizona has the advantage a dry heat. However, experiments show that even in the height of summer heat, concrete temperatures do not exceed 145°F anywhere. In addition, the concrete is a poor conductor of heat and cools slightly when a raw egg is cracked over it. Without an additional heat source, you cannot cook an egg on concrete.
Asphalt, by contrast, can get much hotter. Because concrete is lighter in color, it reflects some heat. Asphalt is much darker than concrete and therefore absorbs and retains heat. In extreme summer heat waves, asphalt has reached temperatures of 158°F-160°F. These temperatures are high enough to modify and coagulate egg proteins, leaving you with something resembling a sunny-side up.
All things considered, we don’t recommend eating either an egg half-cooked on concrete or an egg fully cooked on asphalt. In fact, in extreme heat waves, it’s a good idea to stay indoors and keep any bare limbs of these materials. Cook your eggs on the stove and stay cool this summer!
For more (practical) information on the differences between concrete and asphalt check out our other blog post.