like the ration of said corrosion inhibitor to said coolant can be varied in accordance with the kind use etc of the coolant in most cases however the corrosion inhibitor is used preferably in an amount of from 0 01 to 0 05 by weight of said coolant when it is less than 0 01 by weight no effects may be attained by its addition when it more than 0 5 by weight the freezing curve of the coolant may be adversely affected by its addition and at the same time the coolant could be harmful for the human body if drunken by mistake as a container for enclosing the coolant of the invention there can be used with particular advantage a double walled container made of aluminum or an aluminum alloy although there is no particular restriction therefor aluminum or aluminum alloys which can be used for the container include those not subjected to any surface treatment as well as those subjected to an anodic oxidation treatment to form a protective film on their surface a coolant was prepared by incorporating 100 g of propylene glycol into 1 kg of aqueous 17 by weight solution of potassium hydrogencarbonate this coolant was enclosed within the walls of a double walled container the container was then cooled in a home freezer maintained at 20 u00b0 c whereby the entire coolant was uniformly frozen at 9 u00b0 c the thus cooled couble walled container was taken out of the freezer a mixture of ice cream materials consisting of 200 cc of fresh cream two raw eggs ca 30 g and 45 g of sugar was charged in the container at 10 u00b0 c and an ice cream was prepared therefrom a coolant was prepared by incorporating.