Black icing often comes out a murky gray, which is unacceptable if you want stunning outlines, embroidery or string work, or a show-stopping multilayer masterpiece. To turn white icing jet black, you have to use a lot of black food dye or gel, and too much can make for bitter, chemical-tasting frosting. Instead, start with a cocoa-flavored base and then add color. If you don't have black icing powder, gel or drops, you can use conventional primary paste colors.
Prepare a standard buttercream icing. Measure out 2 cups, and place into a glass or stainless steel bowl.
Add 1/2 cup of cocoa powder to the icing. Mix thoroughly. Add a teaspoon or two of cool water if the icing is too thick. Add the amount of food coloring paste, gel or powder called for by the manufacturer. Some require about 1 ounce per 2 cups of icing. Blend completely so the color is completely distributed.
Add 1/2 cup melted chocolate to the icing as an alternative way to deepen the color of the base. The melted chocolate will affect the texture of the icing and may make it harder to work with.
Taste the icing. If it's bitter, add a pinch of salt. Alternative ways to combat the bitterness are to add another 2 tablespoons of cocoa powder or a teaspoon of a fruit-flavored extract, such as cherry or orange.
You can create black icing from standard primary colors, but this requires high-quality, color-intense pastes or gels; standard liquid food coloring you find in a supermarket is not powerful enough and will result in a grayish icing. Because this method of color mixing requires a lot of food coloring, your icing will likely turn out bitter.
Combine blue, red and yellow food coloring in the icing to create a black color. Usually equal amounts of all the colors turn the icing black, but sometimes you need more red because it's typically less potent than others. You can also add orange instead of additional red to achieve black. Start with a cocoa-infused icing, which is easier to turn black.