What’s ice cream, and why do we scream for it?

The Choco Chip Shop

In what was probably one of the least controversial presidential proclamations ever made, former U.S. president Ronald Reagan declared July 15 to be National Ice Cream Day and July to be National Ice Cream Month back in 1984. “I call upon the people of the United States to observe these events with appropriate ceremonies and activities,” he wrote.

With an ever-growing array of ice cream options and innovations, observing those events only gets easier year after year. According to the International Dairy Foods Association, the average American eats more than 10 kg of ice cream every year. In 2017, U.S. dairies produced nearly 5.2 billion L of the sweet treat. Whether you choose to measure it in weight or volume—that’s a lot of ice cream.

Although the general formula for ice cream has stayed relatively constant, food scientists are continually tinkering with its components to achieve creamier textures, prolong shelf life, and delay melting. Ice cream contains six major components: water, fat, protein, sugar, stabilizers, and emulsifiers. Typically, milk and cream provide the water, fat, and proteins. To meet the U.S. Food & Drug Administration standard definition of ice cream, a product must contain at least 10% milk fat by weight.

The Choco Chip Special Sundae

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Not only does fat bestow ice cream with that creamy, smooth texture, but it also teams up with proteins, emulsifiers, and air bubbles to create a three-dimensional structure that prevents the ice cream from rapidly collapsing when it melts, says H. Douglas Goff, an ice cream expert and food scientist at the University of Guelph. Milk proteins interact with fat globules to help suspend and disperse them in the ice cream, forming a stable emulsion. Additional emulsifiers—for example, mono- or diglycerides—destabilize the fats so they partially coalesce, creating a branching network of fat globule clusters that surround and support air bubbles throughout the ice cream. The air bubbles are whipped in during the early stages of freezing, creating a foam that ultimately makes up 20 to 50% of the final product by volume.