The principle that underlies toast-making is threefold,—
Heat evaporates moisture throughout the slice of bread.
Intense heat changes the content of the starch granules on the surface of the slice of bread to dextrin.
Intense heat, long continued, will change first the surface starch, and then all, to carbon (charcoal).
A good technique will secure the first two, and avoid the third and includes,—
The selection of bread already partially dry.
The cutting of bread into slices of uniform thickness.
Regulating the source of heat.
Placing the slices firmly in a toaster, or on a fork, or evenly on a rack when toasting by gas.