Rock salt, typically sodium chloride, plays a crucial role in the ice cream making process. It’s mixed with ice in the outer chamber of an ice cream maker to create a frigid brine that lowers the freezing point of water. This allows the temperature of the ice and water mixture to drop well below 0C, effectively freezing the ice cream mixture in the inner container quickly and evenly. A typical ratio might involve several cups of ice to one cup of this essential ingredient.
This rapid freezing is vital for producing smooth, creamy ice cream, preventing the formation of large ice crystals. Without it, the ice cream mixture would freeze much more slowly, resulting in a coarse, icy texture. Historically, before the advent of modern refrigeration, this method was essential for creating frozen desserts. It allows for efficient heat transfer away from the ice cream mixture, enabling the freezing process even without access to sub-zero temperatures. The use of such a readily available and inexpensive substance made frozen treats accessible to a wider audience.