Potatoes vary in size and shape. The tubers have thin, smooth skin. The skin ranges in color from pale yellow, cream-colored, to yellow-tan and is sometimes speckled with brown markings and spots, depending on cultivation. Underneath the skin, the golden yellow flesh is firm, dense, and fine-grained with a slippery feel. Potatoes must be cooked and emit a savory, earthy aroma when heated. Potatoes are high in water and low in starch, giving the flesh a waxy consistency with a creamy, smooth, and slightly chewy mouthfeel. Potatoes bear a mild, sweet, earthy, and somewhat nutty flavor. Potatoes are a source of fiber, vitamin C, and iron. The potatoes also provide potassium, calcium, including vitamin B6, manganese, and folate.