Both types of cocoa powder are unsweetened and therefore bitter
when tasted alone.
Dutch-Process Cocoa
or Alkalized Unsweetened Cocoa Powder
has been treated with an alkali to
neutralize its natural acidity.
Because it is
neutral and does not react with baking soda, it must be used
in recipes calling for baking powder, unless there are other
acidic ingredients in sufficient quantities used. It has a
reddish-brown color, mild flavor, and is easy to dissolve in
liquids.
Unsweetened Cocoa has
a complex chocolate flavor while the Dutch-process is darker
and more mellow.
Its intense
flavor makes it well suited for use in brownies, cookies and
some chocolate cakes. When natural cocoa (an acid) is used
in recipes calling for baking soda (an alkali), it creates a
leavening action that causes the batter to rise when placed
in the oven.