The Complete Handbook of Eggs

Chapter 1: Understanding Eggs

Eggs are suspended water, protein, and fat inside a porous calcium shell, and almost everything that matters about them flows from that simple physical reality. A fresh egg is roughly 74 percent water, 13 percent protein, 11 percent fat, and 1 percent minerals, with trace carbohydrates and vitamins. But percentages fail to convey what you are actually handling. You are handling a structure with distinct layers: a cuticle or bloom that seals the shell pores, a calcified shell, two membranes that separate as the egg ages, a thick albumen whose gel structure degrades over time, and a yolk suspended in that albumen by twisted protein strands called chalazae. Every one of those layers has a measurable behavior, and those behaviors are what determine whether your egg poaches into a tidy oval or dissolves into wispy strings, whether your meringue whips stiff or stays flat, and whether your quiche sets up creamy or turns into a water-logged mess.

To use eggs professionally, you must stop thinking of them as a single ingredient and start thinking of them as a system with a clock attached. The clock starts at lay, and its tempo depends on temperature. At room temperature, an egg ages more in one day than it does in one week under refrigeration. The aging process is not merely a matter of the egg drying out. The shell is not solid; it contains thousands of microscopic pores, roughly 7,000 to 17,000 of them, designed for gas exchange