1, from the epidermis:

Iron yam epidermis with purple spots, pore bumps, hair whiskers distribution dense, must be noted: if the yam after finishing, the hair whiskers on it will have to shed, this can not be all do judgement based on the pore bumps on the judgment;

vegetable yam epidermis is relatively smooth, pore bumps and whiskers sporadic distribution.

2, from the yam texture points:

From the yam breaks on the visible: Iron yam texture is very delicate, firm, that is to say, the fiber is very fine, strong, which is the origin of the iron yam, is not easy to break;

And the texture of the vegetable yam fiber is rough, water, pinch the hand can be squeezed out of the water, long more watery, a little touch will break.

3, from the taste points;

Iron yam boiling water pot ten minutes to cook, whether it is steamed or boiled, the taste is dry sweet, and long cooking and not scattered;

vegetable yam, no matter how you steam cooking, it is brittle, so people take it to do the refreshing dishes.