Cheddar cheese is orange because cheesemakers add an orange coloring called annatto during the cheesemaking process. This tradition dates back hundreds of years, originally because the milk from cows eating beta-carotene-rich grass had a natural orange tint. When cheesemakers started skimming cream (which carried this natural orange pigment) to make butter, the remaining cheese lost its color. To maintain the orange hue associated with quality cheese, they began adding annatto, a natural coloring from the seed of the achiote tree, which imparts the familiar orange color without affecting the flavor.
