field.Baking: Air Convection and Radiation
When we bake a food, we surround it with a
hot enclosure, the oven, and rely on a
combination of radiation from the walls and
hot-air convection to heat the food. Baking
easily dehydrates the surface of foods, and so
will brown them well provided the oven
temperature is high enough. Typical baking
temperatures are well above the boiling point,
from 300 to 500ºF/150–250ºC), and yet baking
is nowhere near as efficient a means of heat
transfer as is boiling. A potato can be boiled
in less time than it takes to be baked at a
much hotter temperature. This is so because
neither radiation nor air convection at 500ºF
transfers heat very rapidly to food. Oven air is
less than a thousandth as dense as water, so
the collisions between hot molecules and food
are much less frequent in the oven than in the