A few weeks ago, a boy in Cincinnati accidentally left a Walmart Great Value ice cream sandwich outside. When his mom found it 12 hours later, she was shocked to discover that even on an 80-degree day, the ice cream hadn’t melted.
Then she did what any self-respecting freaked-out person would do: She called the local radio station so she could tell the world about it. When WCPO conducted its own experiment, comparing the meltiness of a Häagen-Dazs ice cream sandwich, a Klondike Bar, and the Great Value ice cream sandwich—lo and behold—Walmart’s version didn’t really melt, while the Häagen-Dazs turned to liquid, and the Klondike bar got kind of soupy.
Why didn’t it melt? According to Sean O’Keefe, a professor and food chemist at Virginia Tech, the more cream—meaning fat—ice cream has in it, the faster it melts. Nonfat ice cream takes longer to melt than fatty ice cream because it has more water in it.
“More water means the ice cream will have to absorb more energy before it can melt. Also, low-fat ice creams tend to have more air whipped into them, which allows them to keep their shape longer,” according to an article in the Pittsburgh Post-Gazette summarizing O’Keefe’s explanation.
When asked about its ice cream sandwich’s stubborn refusal to melt, Walmart gave a different, slightly less profound explanation: “Ice cream melts based on the ingredients including cream. Ice cream with more cream will generally melt at a slower rate, which is the case with our Great Value ice cream sandwiches.”
Walmart’s Great Value ice cream sandwiches contain corn syrup, guar gum, and cellulose gum—all ingredients that could also contribute to their failure to melt. Häagen-Dazs ice cream doesn’t have any corn syrup or “gums of any type,” said WCPO.
For the record, according to the FDA, it’s safe to eat ice cream with corn syrup and those “gums”—though maybe not after it has spent 12 hours in the sun.