The questioner wants to ask what is the color corn that Shake Shack anchors eat and that looks like coffee? PurpleCorn. Purple corn is a corn variety unique to Peru, the corn cob and kernel are purple. The color is similar to coffee beans. The plant, which is native to the Andes, is extremely high in phenolic compounds and anthocyanins. Purple corn is the purple (black) corn family of treasures, so purple corn is also known as black corn, because the grain is shaped like a pearl, so it is called the black pearl. It plant height of about 1.5 meters, maturity period of about 100 days, just into the grain, was crystalline ivory color, grew up gradually into light red, matured into purple, dried into purple-black, stick length of about 10cm, thousand grains weighing about 120 grams.