A look: iron rod yam is uniform in thickness, generally 1-2 cm in diameter (like an adult thumb), the skin is dark in color, and the rhizome has iron scars; if the diameter is too thick or the skin is too lubricious, it means that it is not authentic. Erji: The weight of a single stick of yam is generally about 200 grams; if it is too heavy, it may not be authentic. 30% off: Broken iron yam, you can feel the meat is hard, powdery enough, its cross section is delicate, white or slightly yellow teeth, and less mucus; ordinary yam not only is not so hard and not powdery. Four tastes: Due to the low water content and rich yam polysaccharide content in iron yam, its liquid juice is thicker, the taste is dry and sweet after cooking, and the mouth feels "face and sweet", with a slight tingling taste .

At present , many vegetable vendors in the market claim that the yam they sell is wild yam . In fact , most of the yam on the market is artificial cultivation , and there are not many wild yams . Artificially cultivated yam is generally relatively straight , contains more water , and its skin is more lubricated . It is very attractive ; while real wild yam has a harsh growing environment , the shape of the grown yam is not regular , it is hard and solid , the water content is small , and the thorn is relatively many .