What is refrigerant? Refrigerant is a substance used to cool or freeze somthing, especially the liquid that circulates in a refrigerator. 

Before making ice cream, please put the freezing cup into the freezer of the refrigerator (freezer temperature is lower than -18℃) and leave for at least 12 hours, take it out and shake it. If there is no liquid shaking sound, it is well frozen.