If you use too much food coloring, your frosting or food may end up with a bitter taste. This is because the liquid and gel dye can alter the flavor. The bitter taste is most evident with the liquid food coloring. If you want to ensure that your icing or frosting tastes good, consider adding less than 1/8 teaspoon of black food color at a time until desired shade is achieved, then mix well before adding more food coloring. To avoid an unpleasant aftertaste, mask sure you use only a small amount of black food coloring. To make your frosting an even darker shade of black without adding more dye, you can add cocoa powder to your frosting or icing for some extra flavor. You may also want to consider using natural food coloring.