The cake families, sorted by how the air gets in

Culinary categories overlap and no formal standard governs them, so this is a pragmatic classification rather than a scientific one. It is useful because it predicts behaviour.\n\nCREAMED CAKES aerate by beating air into solid fat with sugar crystals. Victoria sponge, pound cake, most everyday cakes. The method depends on butter being plastic, which is why softening it matters and why melting it ruins the mechanism.\n\nFOAM CAKES aerate by whisking air into egg. Genoise, angel food, chiffon. There is little or no solid fat to trap air, so the foam IS the leavening — which is why folding rather than stirring is non-negotiable and why these collapse if handled roughly.\n\nOIL-BASED CAKES do not aerate mechanically at all. Carrot cake, many chocolate cakes, muffin-method loaves. A liquid fat cannot hold air, so the lift comes from a chemical leavener and sometimes from egg. They are the most forgiving to mix and the least forgiving to over-leaven.\n\nCUSTARD-SET CAKES are barely cakes in the structural sense. Cheesecake is set by egg protein coagulating rather than by a flour structure holding gas, which is why it is baked gently, often in a water bath, and why it cracks rather than sinking.\n\nFLOURLESS CAKES remove the starch structure entirely and rely on egg and sometimes on chocolate setting. Dense by design rather than by failure.

Each family fails in a way that follows from its aeration.\n\nA CREAMED CAKE fails when the fat was the wrong temperature — too cold and it never aerates, too warm and the emulsion breaks and the air escapes. Its characteristic faults are density and a greasy, coarse crumb.\n\nA FOAM CAKE fails when the foam is damaged: over-folded, left standing, or contaminated with fat. Its characteristic fault is a flat, rubbery layer at the base.\n\nAN OIL-BASED CAKE fails on mixing and leavening rather than on aeration, because there was no aeration step to get wrong. Its characteristic faults are tunnelling from overmixing and collapse from too much raising agent.\n\nA CUSTARD-SET CAKE fails on temperature, because egg protein overcooks into a grainy, weeping texture within a narrow range.\n\nThat is the practical value of classifying at all: knowing which family a cake belongs to tells you which questions to ask when it goes wrong.

Plenty of real cakes sit between families, and pretending otherwise would be a tidier scheme and a less useful one.\n\nA Victoria sponge is creamed and is called a sponge, which in strict usage means a foam cake. Chiffon uses both a whisked egg-white foam and oil. Many chocolate cakes are creamed, oil-based and chemically leavened at once. Brownies are a cake by ingredient and a confection by texture, and BakeHQ files them by method rather than arguing.\n\nThe families are a lens rather than a filing system. When a cake sits between two, it usually inherits the failure modes of both — which is the most useful thing the classification can tell you about it.