An ounce of semi-sweet chocolate in a recipe can be substituted with 1 ounce of unsweetened baking chocolate with 1 tablespoon of granulated white sugar. If the recipe calls for a larger quantity, the substitution can be doubled, tripled or quadrupled as necessary. The quantity also can be halved easily for a smaller amount.
Semi-sweet chocolate also can be substituted with unsweetened cocoa powder. A tablespoon of unsweetened cocoa powder is combined with 2 teaspoons of white granulated sugar and 2 teaspoons of melted butter, vegetable oil or shortening to replace 1 ounce of semi-sweet baking chocolate.
Unsweetened chocolate cannot be substituted for recipes in place of semi-sweet chocolate chips, such as chocolate chip cookies. The substitutions above are best used for recipes that use baking chocolate, such as brownies. Substitutions also are not recommended when making most candy recipes, since such recipes typically require very specific combinations of ingredients in order to reach the appropriate boiling points and consistencies.
Unsweetened chocolate comes from cocoa beans. A machine transforms the beans into a bitter paste of cocoa solids and cocoa butter. The addition of sugars, vanilla and other ingredients make the chocolate palatable. In the United States, semi-sweet chocolate is a type of dark chocolate that contains at least 35 percent cocoa liquor.