Why is salt sprinkled to ice in making ice cream?

Answer 1

The ice cream freezes because the rock salt and the ice mix to make a substance with a lower freezing point than ice alone.

Answer 2

When mixed with ice, some chemicals decreases the temperature of the mixture.
(Ref: Dubbels, 1.Band, SpringerVerlag-1953- Page747- Kaeltemischungen mit Eis).

Examples: (mixture : weight of chemical / weight of ice )

1. NaCl ( 23.3/100 parts ) : -21.1 Celsius

2. KCl ( 19.75 / 100 parts ) : - 11.1 Celsius

3. CuCl sub2 ( 36 / 100 parts ) : -40 Celsius

Very interesting that:
4. HCl (24.8 / 100 parts ) : -86 Celsius

Normally water starts to develope the ice at 0 degree Celsius, but 100 grams of crushed ice mixed with 36 grams of Hydrochloric acid shall produce a mixture temperature of minus 86 Celsius !.

(Please Note That : Celsius degree = Centigrade degree )

Back to your question:

For making the ice cream we need a temperature less than 0 degree celsius. Because the milk and other ingredients form a mixture and the so called cryoscopical temperature of the mixture is less than 0 degree Celsius ; i.e. the mixture cannot forms the ice crystal lattice, at zero degree Celsius..

For that reason we have to find a method to cool the ice cream mixture to an appropriate temperature , for instance minus 10 or minus 15 degree Celsius.


" NaCL + crushed ice" makes a temperature of - 21 Celsius and cools the ice cream mixture being in a bowl ( or in a metal vessel ) . The milk and ingredients mixture freezes and ice cream is produced.

Another point is the heat transfer through the walls.

If the outer temperature of the ice cream vessel ( bowl ) is 0 Celsius, the inside ( milk and ingredients mixture ) temperature can not reach to 0 degree Celsius.

For heat transfer from the inside to outside through the wall of the bowl, a temperature difference is needed.

For that reason we have to have a cooler outer mixture .

The Salt + Ice mixture is a perfect combination for the purpose.

Answer 3

When making ice cream, the warmth of the ingredients in the mixing container is transferred to the ice-slush mixture surrounding it. This makes the ice melt, and an average temperature results. Ice @ 32 degrees Fahrenheit mixed with room temperature ingredients will result in a temperature in the mix that is not low enough to freeze it into ice cream.

Mixing salt - rock salt for economy - with the ice-slush lowers the freezing point of the slush. Thus, contact between the slush and the ice cream mix will result in an average temperature which is low enough to freeze the mix into ice cream.

;-D Chocolate is still my favorite, although there are lots of great fruit recipes!

Answer 4

Makes it colder so your ice cream freezes more quickly.

I remember as a kid, my grandparents had the old hand crank ice cream maker. They would have one of us kids sit on top of it (on a stack of newspaper) about halfway through the process because enough ice would've melted that the canister w/the ice cream in it would start to float.

Those were some good times...mamaw's homemade ice cream. *drools*

Thanks for jogging that memory. :)

Answer 5

BECAUSE A SALTED ICE CREAM WOULD TASTE BETTER.

DON'T ASK SUCH TYPE OF QUESTIONS ANYMORE AND I AM FORCING YOU TO VOTE MINE AS THE BEST ANSWER.

Answer 6

ice melts faster and produces more cold temperature