No, according to Netease News Network, dried alum will slowly dissolve in hot water, and impurities have precipitated, so there will be no precipitation after cooking. Also called calcined alum. Take out the dried alum, heat and melt it in a casserole, and calcine it to dryness. After being taken out, it is irregular crystals with different sizes, colorless, transparent or translucent, slightly smooth or uneven surface, fine longitudinal edges and glass-like luster.