The length of time mainly depends on how much milk you have and the freezing capacity of the refrigerator. The more milk, the longer it takes.

The back of each refrigerator is marked with the freezing capacity in kilograms, indicating how many kilograms of beef can be frozen from 25℃ to-18℃ in 12 hours.

I tried to put 1 liter of water in the freezer, and it was completely frozen in one night, about 7-8 hours.

Of course, if you need less frozen milk, for example, only 250mL, it is estimated that 2 hours will be enough.