Why is my buttercream frosting not white?

Clear vanilla is one of the best ways to keep your buttercream frosting as close to white as possible. If you use traditional or even artificial vanilla, it will turn your buttercream frosting into more of a cream color rather than pure white. Pure white buttercream does not exist, as the color of butter is slightly yellow, which will give your buttercream frosting a small amount of color. However, the most likely culprit of your tan buttercream is your traditional vanilla extract.