Chocolate cake
A creamed or blended cake containing cocoa solids, whose acidity and starch content change how the batter is leavened and how the crumb sets.
Chocolate cake is not simply a plain cake with cocoa added, and treating it as one is where most of its faults originate.
Cocoa powder is largely starch and fibre, and it absorbs water. Substituted for flour by weight it removes gluten-forming protein while adding an aggressive absorbent, which is why a straight swap gives a dry, crumbly result. Natural cocoa is also acidic, which affects chemical leavening directly: it will react with bicarbonate of soda, whereas Dutch-processed cocoa has been alkalised and largely will not.
That interaction is the reason recipes for chocolate cake specify which cocoa they were written for, and the reason substituting one for the other without adjusting the leavening changes both the rise and the flavour.
What it should be like
- Crumb texture
- Fine and tender, without the coarse tunnels that indicate overmixing
- Moisture
- Moist without being dense; cocoa’s absorbency makes this harder to hit than in a plain sponge
- Browning
- Colour comes mostly from the cocoa; surface browning reactions contribute less than in a pale cake
How it keeps
Keeps better than a plain sponge of the same size, generally attributed to a higher fat and sugar content holding moisture and to the crumb’s lower gluten content.
Recorded as inferred: the observation is widely reported by bakers and the mechanism is plausible, but no source in the register was consulted specifically for it.
InferredEstablished practice, not a measured result
Natural and Dutch-processed cocoa are not interchangeable
Natural cocoa is acidic. Dutch-processed cocoa has been treated with an alkali, which raises its pH, darkens it, and softens its flavour.
Where a recipe uses bicarbonate of soda alone, it is relying on an acid in the batter to react with it, and natural cocoa is often that acid. Substituting Dutch-processed cocoa removes the acid and leaves the bicarbonate largely unreacted — producing less lift and a soapy, mineral taste from the residue.
Where a recipe uses baking powder, which contains its own acid, the substitution is far less consequential. This is the single most useful thing to know before changing a cocoa in a recipe.
Related
Part of
A creamed batter set by egg and starch around mechanically and chemically produced gas.
Characteristic ingredients
Eggs supply the coagulating protein that sets the crumb and the emulsifiers that keep the fat dispersed.
Natural cocoa is acidic and can supply what bicarbonate of soda needs — which is exactly why swapping in Dutch-processed cocoa causes trouble.
Techniques involved
Creaming creates the gas cells the leavener later expands, which is why more baking powder cannot rescue a poorly creamed batter.
Things that go wrong
Cocoa’s absorbency and the acid-leavening interaction give this product more ways to reach the fault than a plain sponge has.
The product where uneven baking is noticed most, because a cake records the unevenness in its shape as well as its colour.
An egg-free bake came out dense or gummy
Commonly adapted, and the failure is usually structural rather than a matter of taste.
Buttercream is runny, split or grainy
Where a buttercream most often meets a bake, and where a split one is most visible.
The product the question is most often asked about.
The cake is dense and did not rise
Recorded because the V3 demand asks about this fault under this product name, not because the fault belongs to it alone.
The cake domed and cracked on top
Recorded because the V3 demand asks about this fault under this product name, not because the fault belongs to it alone.
The cake is raw, wet or gummy in the middle
Recorded because the V3 demand asks about this fault under this product name, not because the fault belongs to it alone.
What this product needs done
Aeration
A cake without aeration is not a dense cake, it is a different product. This is the requirement most egg substitutions fail, which is why 'can I bake a cake without eggs’ has a conditional answer rather than a yes.
Structure building
Something has to set around the gas cells or they collapse as the batter warms. In cake that work is shared between egg protein and starch.
Gluten inhibition
Cake is bread with the structure deliberately restrained. Without something inhibiting gluten the result is tough rather than tender.
Hydration
Water is required for the starch to gelatinise and set the crumb at all.
Emulsification
A creamed batter is fat and water held together. Without emulsification it splits, and a split batter bakes coarse and greasy.
Techniques this product depends on
The aeration a creamed cake depends on is mechanical and comes from this step. A chemically leavened batter expands cells that creaming created; without them there is far less to expand.
Covered in
The cake families, sorted by how the air gets in
Commonly creamed, oil-based and chemically leavened at once — one of the cakes that sits between families.