adding a soluble solid, such as table salt, will dissolve in water and will increase the boiling poing of water (one reason for adding salt to pasta water) or to lower the freezing point of water (road salt on black ice makes water). The more salt you put in will have more of an effect, as sds shows in his formula. AD's 22 degrees is a funtion of the ambient air temperature, the cooler's effectiveness, and the amount of salt added to the water. Now, if the air temp is below 22, then the water will get below 22, depending on how much salt is added. As for me, i throw the beer in the freezer for a good half an hour. The freezer goes around 0 degrees farenheit, so i'll have a couple slow drinks then remove the rest for the fridge and it's ice cold.