The chocolate percentage is worked by comparing the amount of chocolate (including cocoa solids and cocoa butter) vs. sugar used within a recipe. For example, for 70% dark chocolate, you'd use: 70% cocoa liquor (which contains both the solids and butter) 30% sugar (dried - NOT liquid). OR, if you're using the manual grinding process and adding extra cacao butter to the mortar and pestle: 65% cacao nibs 5% cacao butter 30% sugar (dried - NOT liquid). 65% is neither sweet nor bitter; it's that lovely middle range. 70% is the beginning range of a good dark chocolate 'bittersweet' flavor. You can use a combination of the cocoa nibs and cocoa powder/ cocoa butter to finely tune the % you want the chocolate to be.