Why was the saltis added to ice in the old method of making home made ica cream?

Answer 1

When the ice melts, the salt mixes with it and keeps it from refreezing (saltwater freezes at a higher temperature), thereby keeping the ice/water mixture at a steady temperature. The ice melting in itself is a endothermic reaction, taking more heat than it releases, thereby cooling the cream mixture.

Answer 2

Salt water freezes at a lower temperature than the fresh water in the ice. When you add salt to the ice some of it dissolves in the thin film of water on the ice and slowly starts to diffuse into the surface of the ice crystals. These salty ice crystals are now too hot to stay solid but they need to get a lot more heat from somewhere (used to be called the latent heat of melting or some such thing) to be able to melt. So they get the heat they need to melt ,from the bowl containing the ice-cream mixture and that rapidly cools the ice-cream mixture down.

Best of Luck - Mike

Answer 3

The salt melted the ice, but didn't increase the ice's temperature. Ice water has more surface area than ice alone, allowing greater transfer of cold to the ice cream through the metal container.

Answer 4

Salt lowers the freezing point of water, so ... at the same temperature, ice + salt will melt faster than ice alone.

As it melts, it absorbs heat energy from its surroundings in order to make the transformation from ice to water. As it crosses this barrier, it absorbs 80 calories per gram (as opposed to 1 calorie per gram to raise its temperature one degree centigrade while it's in either its solid or liquid state). This is a relatively *tremendous* amount of energy, and it's this energy that is absorbed from the ice cream mixture in the churn, causing it to freeze.

In simpler terms, ice cools MUCH more efficiently when it's melting, and the salt causes the ice to melt.

And we all get to enjoy homemade ice cream!

Good question!

Answer 5

Otherwise the ice would stick together and not melt as quickly - it's the turning and the melting ice that transfers the cold to the ice cream and makes it take.

Toodles