This depends exclusively on your receipt; of course under 0 0C !
32 degrees F
When salt is added to ice, it lowers the temperature of the ice. This causes the ice to melt and absorb heat from the surrounding environment, including the ingredients of the ice cream mixture. The lower temperature of the ice helps freeze the mixture, resulting in the formation of homemade ice cream.
The purpose of using salt when making homemade ice cream is to lower the freezing point of the ice surrounding the ice cream mixture, allowing it to freeze at a lower temperature and create a smoother texture.
You add salt to ice to lower the temperature of the ice/water mixture. Without the salt, the temperature would not fall below 32F, which is not cold enough to make ice cream. The freezing point of salt water is below that temperature and thus allows the cream to partially freeze, a necessary part of making ice cream Salt causes water to freeze at a much lower temperature. Adding salt to the ice causes the temperature of the brine solution to drop dramatically, while freezing the ice cream inside the container. As the ice melts, the "heat" of the ice mass is preserved by lowering the temperature. (It's called "latent heat") It takes approximately 80 calories of energy to melt a gram of ice. That latent heat principle is used to lower the temperature of melting ice, thereby allowing the ice cream to freeze. It's an example of simple physics and is described in most physics books and physics classes.
Ice cream is a liquid at room temperature. hence "ice"-cream. ice melts when its temperature increases to over 00C
You add salt to ice to lower the temperature of the ice/water mixture. Without the salt, the temperature would not fall below 32.F, which is not cold enough to make ice cream. The freezing point of salt water is below that temperature and thus allows the cream to partially freeze, a necessary part of making ice cream Salt causes water to freeze at a much lower temperature. Adding salt to the ice causes the temperature of the brine solution to drop dramatically, while freezing the ice cream inside the container.
Temperature in an ice cream lab shouldn't drop: the thermostat there should be set at the appropriate temperature for keeping ice cream in the optimum condition.
To lower freezing point, making the ice cream mix in the container colder than freezing temperature so it freezes faster. Its much easier to make ice cream with a compressor freezer than a salt & ice freezer.
ice
You don't use rock salt in ice cream, unless you want salty ice cream. You use rock salt (though table salt or sea salt would work just about as well) in the freezer to get it colder than you could with a mixture of ice and water.
The salt makes some of the ice melt (by reducing its melting temperature). The mixed ice/water/salt is now several degrees below the normal freezing temperature of water and causes the ice cream miix to freeze faster.
It lowers the temperature of the freezing solution