Dutch processed chocolate or Dutched chocolate gets its name from its inventor Conrad van Houten, who was Dutch. This chocolate had been treated with an alkalizing agent to intensify its its colour and give it a smoother more mellow flavour compared to a natural cocoa powder.
The alkalizing substance used is called potassium carbonate and apart from modifying the colour and flavour it also raises the pH to a neutral 7 or alkaline 8.
The benefit of a Dutch chocolate is that because it is not acidic it won’t react with alkaline leaveners like baking sodas to produce carbon dioxide. Therefore if a recipe says you need to use Dutch chocolate it will probably tell you to use baking powder as a leavening agent, so that they can both react and produce carbon dioxide.
In simplified terms a Dutch chocolate has been alkalized with potassium carbonate to darken the colour and give it a milder taste. Whereas Cocoa powder is plain natural chocolate which has not been alkalized, therefore it remains acidic.
This is the reason why I only use DeZaan Dark Cocoa Powder which is natural (alkaline free) and comes from Netherlands in all my chocolate cakes and sweets.
Con Amor Gabriela X