On Food and Cooking

of jade. We see the first layer of structure
whenever we cut into a hard-cooked egg.
Where heat gels the white into a smooth,
continuous mass, the yolk sets into a crumbly
mass of separate particles. The intact yolk
turns out to consist of spherical compartments
about a tenth of a millimeter across, each
contained within a flexible membrane, and so
tightly packed that they’re distorted into flat-
sided shapes (much like the oil droplets that
egg yolk stabilizes in mayonnaise; see p. 626).
When a yolk is cooked intact, these spheres
harden into individual particles and give the
yolk its characteristic crumbly texture. But
break the yolk out before you cook it so that
the spheres can move freely, and it becomes
less granular.