Toast is bread that has been browned by exposure to radiant heat. The browning is the result of a Maillard reaction, altering the flavor of the bread and making it firmer so that it is easier to spread toppings on it. Toasting is a common method of making stale bread more palatable. Bread is often toasted using a toaster, but toaster ovens are also used. Pre-sliced bread is most common.