Using an old fashioned ice cream maker, why is salt added?

Question

Most accurate answer gets 10 points. "Because it makes it colder" is not good enough.

Interesting assortment of answers so far!

What most people and websites explaining how an ice cream maker works fail to point out is that ordinary ice taken out of the freezer is already well below 27 degrees Farenheit. But once it starts to melt, the slush is at 32 degrees Farenheit. Adding salt ensures that the slush will stay much cooler, even though it's true that an endothermic process is happening. For some reason, many people seem to believe that ice is always 32 degrees Farenheit.

Answer 1

Since ice cream mix begins to freeze at 27 Fahrenheit (-3 Celsius), the container in the ice cream maker must be cooled to, or below, that temperature. Ice made from regular water is inadequate for cooling the container. That's because once the ice melts, the meltwater is warmer than 32 Fahrenheit (0 Celsius).

Salt water, however, has a lower freezing temperature than regular water; a saturated salt solution freezes at -6 Fahrenheit (-21 Celsius) (saturated means the water contains the greatest possible amount of salt in solution).

When salt is put on ice, it dissolves on the ice's watery surface. In the process, heat is absorbed. The salt also causes the ice to melt quickly—another process that absorbs heat from the surroundings. The slushy ice/salt mixture remains well below the temperature necessary to freeze ice cream

Answer 2

Old Fashioned Ice Cream Maker

Answer 3

I think you can use any recipe in any ice cream maker. It is only the method of freezing it that is changed. My ice cream maker is only about 40 years old but then they made these small kitchen appliances to last. Now if they last a season, you are darned lucky. Use any recipe you find that sounds good and fill only to the line indicated and then do whatever it takes to make the ice cream.

Answer 4

The reason you might add very low amounts (O.1%) of salt to your ice cream mix before freezing is that it will make the ice cream stiffer, more dry and gives a glossy appearance.

In the second case, salt (sometimes rock salt) is added to the ice used to freeze the mix in order to lower the temperature of the freezing medium so that the ice cream mix will freeze quicker. It will freeze quicker because the temperature of salt water can be lower than that of fresh water. The end result is that you have firmer ice cream which melts more slowly.

Answer 5

Salt added to ice lowers the fusion point of water, and by forcing it into liquid form, cause it to absorb its latent fusion heat. This in turns makes the temperature of the brine lower than that of the original ice.

Answer 6

In good old days salt was added for taste. They also did not bother to reduce milk fat and used plenty of sugar and eggs.

Nowdays the taste of ice-ream reminds mostly frozen coca-zero.

Answer 7

Because pepper would make one sneeze!