My understanding is that Edam is basically the same make process as Gouda, except that Edam was traditionally made with part-skim milk, and traditionally formed into a ball shape. So otherwise, it is a lower-fat Gouda. Some recipes also call for scalding the rind of the cheese after a little bit of pressing - at the point when you would perform the first or second flip in the press, the cheese is placed in hot water for a few minutes. This helps close the rind but also gives it a slightly different texture.