Cocoa powder is an unsweetened powder made from cocoa beans. The nibs from the dried beans are ground and the fat (cocoa butter) is extracted. The result is a dark brown paste called chocolate liquor. This paste is dried and then ground into a powder. This powder is unsweetened cocoa.
Dutch cocoa, which is darker and richer, has been treated with an alkali, such as baking soda, which helps neutralize cocoa’s natural acidity.