How to make lotus root slices with vinegar sauce crisp and not black? Clean the fresh lotus root first, then peel it with a peeling knife, and then rinse it with clear water to ensure cleanliness. Then cut the lotus root from the middle, cut it into semi-cylindrical pieces with a thickness of about 2 cm, and then put it in clean water. Then prepare to boil a pot of water, put the sliced lotus root into the pot, blanch and take it out, then put the prepared sugar and vinegar into the pot, add a proper amount of water, salt and a small amount of starch, and then put the prepared lotus root slices into the pot so that the soup can be eaten out of the pot.