This is two tablespoons of cocoa powder combined with two tablespoons of water and a teaspoon of baking soda. If you look closely you can see that an interesting chemical reaction is taking place. See there? Right along the edge where the mixture meets the dish? A little reddish tint. Look close now…see it there?
Of course you don’t. There’s nothing happening. Well maybe something is happening, but certainly nothing that’s going to turn chocolate red, not even a little. Yet there’s a persistent myth in American baking culture that chocolate cakes, with a little chemical manipulation, can be made to look reddish. “Red” velvet cakes, “red devil” cakes, “devil’s food” cakes, are all supposed to be reddish because the chocolate they contain is reacting with…something-or-other. Soda. Acid. One of those.
I’m not entirely sure why this myth has persisted so long. Maybe because it’s a hard claim to positively disprove chemically. Like coffee, chocolate contains scores (maybe hundreds) of chemical compounds we know next to nothing about. Maybe one of them might react with something to make it sort of, er…reddish. Maybe? No, not really. We’ve already seen what chocolate does combined with a large quantity of a kitchen alkaline. Here’s the same chocolate-water mixture combined with a tablespoon of vinegar (acid).
Still nothing. What if we put large quantities of both in there? Looks like my polluted brain. But at least something’s happening this time, even if it isn’t red. I snapped this picture just before this goop bubbled and foamed all over my work surface. What a mess.
So how did the idea of a red chocolate cake get started? It’s a darn good question. The only thing that occurs to me is that way back in the earliest days of chocolate, indigenous peoples in the Americas combined liquid chocolate with crushed achiote (annato), a bright red dye, to give it a ritual blood-like color. Perhaps this is where the myth of the red chocolate originated, but I can’t say for certain. All I know is you can’t turn chocolate red with anything you commonly find in a kitchen. Other than lots and lots of red food coloring.