點解完crstallization 要用凍水洗crsytal? (English)

It is because the structure of crystals may be damaged when it is heated and expands.
Also, the crystals may dissolve and liquify.

Due to the hot water having higher solubility than the cold one, if we use hot
distilled water to flush the crsytal, then more part of crsytal will be dissolved.