Here are 5 Cool Facts About Ice Cream:
1. Long before modern refrigeration and freezers, around 200 BC, the Chinese enjoyed a frozen mixture of milk and rice sweetened with syrup. It was made frozen by pouring snow mixed with an ancient salt over the ingredients. Roman Emperors have been known to have snow retrieved from mountaintops in order to create the finest chilled delicacies. The Ancient Greeks, around the year 400 AD, ate snow mixed with honey and fruit in Athens.
2. Air is a key ingredient in ice cream (and is what makes it a foam). Although it is not listed in the ingredients, air makes up approximately a third to one half of the total volume of ice cream. When the ingredients in ice cream are whipped together, air bubbles get beaten into the mixture. Often in an ice cream maker, a blade will continuously move throughout the mixture to aerate it, or move air through it. You must whip together and freeze the ingredients all at the same time in order to create and suspend the most important ingredient – air bubbles! Air is what gives ice cream its light. smooth texture. It’s also what escapes as ice cream melts, which is why ice cream shrinks down and is never quite the same after you refreeze it. Ice cream is a foam — a light mass of fine bubbles formed in liquid.
3. Ice cream is an emulsion. Under normal circumstances, if you simply mixed the ingredients in ice cream together, they would quickly separate apart. The fat globules from the milk would rather stick together than be spread out among ice crystals, air bubbles, sweeteners, and flavorings. To truly make it an emulsion, which is a mixture of liquids in which one liquid is scattered throughout the other but is not dissolved, you can whip up the ingredients to really spread them out and then trap them timelessly by freezing them so they won’t “escape.”
4. One key to creating this foamy emulsion – whether in an ice cream maker or in a plastic baggie – is to freeze it quickly. While the ingredients are being whipped together, the liquids will only turn into ice crystals if they are cooled with something that is even colder than ice. That is why rock salt is added to the ice that surrounds the barrel in ice cream machines or in the baggie of ice you can use to make ice cream yourself at home. The ice cream must be frozen quickly so that the liquid ingredients will turn into ice crystals that will “trap” all the other ingredients, including all those air bubbles, in place.
5. The discovery of the freezing-point depression was a real game-changer in the history of ice cream making. Adding salt to ice artificially lowers the freezing point of water. This is called freezing-point depression. The discovery of this principle was a real game-changer in the history of ice cream making. Before this, people had to make do with mixing ingredients with snow and ice to make a chilled delicacy. But once people discovered how to lower the freezing point of liquids (by adding rock salt to ice), they could not only chill their mixture – they could freeze it. And that is how we got ice cream!
