A toaster is a kitchen appliance for toasting food such as sliced bread, crumpets, and bagels. Toasted bread is called toast. A typical toaster uses heat radiated from hot electric elements to heat a piece of bread. The toasting process consists of reducing the bread's water content, raising its temperature, and slightly charring and caramelizing its surface. The caramelizing process is a chemical reaction in which the complex starch molecules break apart into simpler sugar molecules upon heating. That is why toast is usually sweeter than normal bread.
More recent additions to toaster technology include the ability to toast frozen bread (as with the toaster pictured), separate operation levers to allow users to toast either two or four slices, and reheating functions which allow toast to be warmed without being burned.