Created in Niagara County, New York, in 1868, Niagara grapes are medium to large in size and are globose in shape. Plus, they have a firm, glossy skin that is crisp and sweet with a slightly musty flavor. In addition, these grapes are an excellent source of vitamins C, K, B1 and B6, as well as minerals like potassium and manganese. As a matter of fact, a high potassium intake has been associated with a reduced risk of stroke, protection against loss of muscle mass, and preservation of bone mineral density.