In short: Dutch-processed cocoa is the same cocoa powder treated with an alkaline solution. The treatment lowers acidity, darkens the colour and softens the flavour. Natural cocoa is acidic and lighter — and it is the one that works in recipes raised with baking soda.
What Dutch processing does
Dutch-processed cocoa is a product of the same cocoa bean, additionally treated with an alkaline solution. That treatment changes the flavour, aroma and colour of the powder.
The alkali neutralises the natural acids in the bean. The colour shifts towards deep brown or almost black, the sharp edges of the flavour disappear, and what remains reads as rounder and softer.
Natural cocoa
Untreated cocoa keeps its acidity. It is lighter in colour, more astringent and more clearly fruity — and that acidity is exactly what makes it work in recipes leavened with baking soda.
Which one to choose
The choice is dictated by the raising agent, not by taste alone. If the recipe relies on baking soda, it needs the acid that only natural cocoa provides. If it uses baking powder, which already carries its own acid, Dutch-processed cocoa is the better option — its colour and flavour are more predictable.
In mousses, ganaches and glazes, where nothing has to rise, use whichever suits the colour and flavour you are after.
Frequently asked questions
How do Dutch-processed and natural cocoa differ
In acidity, colour and flavour. The alkali neutralises the acids, so the colour goes dark and the taste becomes milder and rounder.
Which cocoa should I use with baking soda
Natural, untreated cocoa: the soda is activated by its acidity. With Dutch-processed cocoa there will be no rise unless the recipe contains another acid.
How can I tell which one I have
Look for the words alkalized or Dutch-processed on the label. If there is no such note, the powder is usually natural.