At first glance, the iron stick yam is uniform in thickness, with a diameter of 1-2 cm (like an adult's thumb), slightly black in skin and iron-red spots on the root; If the diameter is too thick or the skin is too smooth, it means it is not authentic.

Second, the weight of iron stick yam is generally not more than 200 grams, that is, four or two; It's too heavy. It may not be authentic.

30% off: when the iron stick yam is broken, it can be felt that its meat is hard, full of powder, delicate section, white or yellowish, and less mucus; Ordinary yam is not only not so hard, but also not enough powder.

Four flavors: Because the iron stick yam contains less water and is rich in yam polysaccharide, the juice is thick, and it tastes dry, greasy and sweet after cooking. The entrance has the feeling of "sweet with sweet" and is accompanied by a faint hemp taste.