Devil's food cake is a moist, airy, chocolate layer cake. Devil's food cake is considered a counterpart to the white or yellow angel food cake. Devil's food cake is chocolate-flavored, and is differentiated from other chocolate cakes by the use of more baking soda (sodium bicorbonate) which raises the PH level and makes the cake a deeper and darker mahogany color.
Devil's food cake is more moist and airy than other chocolate cakes and often uses cocoa as opposed to chocolate for the flavor. Devil's food cake incorporates butter (or a substitute), egg whites, flour (while some chocolate cakes are flourless) and less egg than other chocolate cakes. Devil's food cake was introduced in the United States in the early 20th century with the recipe in print in 1905.
The lack of melted chocolate is typically what distinguishes a 'devil's food cake' from a chocolate cake. The use of hot, or boiling water as the cake's main liquid, rather than milk, is also a common difference. The cake is usually paired with a rich chocolate frosting.
A similar cake, the red velvet cake, is closely linked to a devil's food cake, and in some turn of the century cookbooks the two names may have been interchangable. When used in cakes, baking soda causes reddening of cocoa powder when baked, and before more alkaline "Dutch Processed" cocoa was widely available, the red color would have been more pronounced. This natural tinting may have been the source for the name "Red Velvet" as well as "Devil's Food" and a long list of similar names for chocolate cakes.