The difference between ice cream and soft serve ice cream actually comes down to USDA regulations, according to which, ice cream must consist of 20 percent cream, 10 percent milk, and at least 10 percent fat. Premium ice cream brands like Ben & Jerry's, for example, use closer to 15-20 percent fat in their ice cream, making it creamier, richer, and incredibly delicious.

Ice cream from cheaper brands, on the other hand, tends to contain more overrun, which is basically the amount of air churned into the ice cream to make it lighter and fluffier. The key difference between soft service and regular ice cream is that soft serve ice cream contains less milk fat and more overrun than regular, hard ice cream.

The machine used to make soft serve ice cream keeps it soft with a smoother texture by incorporating air into the ice cream while churning it — more air than is found in hard ice cream. The machine is also responsible for not allowing the ice cream to harden too much by keeping it cool enough but not too cool.