In the 1500s, an Italian scientist named Giambattista della Porta made a discovery near and dear to many a frozen dessert lover's heart: By mixing salt and snow, you could lower the melting point of ice.
Della Porta used this discovery to freeze wine in a glass of salt and ice. Specifically, he took a vial of wine, added a dash of water and immersed it in a wooden bucket full of snow mixed with saltpeter, then turned the vial round and round. The saltpeter made the snow colder than it would have been otherwise, allowing the wine inside the vial to freeze.
Others soon heard of this phenomenon and figured out common salt would work as well, and they began using the technique to whip up not just wine slushies but other iced treats. "Cooks dipped fresh fruits in water, froze them until their icy exteriors sparkled, and then displayed them. They set marzipan boats afloat on seas of ice. They created tall pyramids of ice with fruits and flowers frozen within them," Geraldine Quinzio recounts in Of Sugar And Snow: A History of Ice Cream Making.
Eventually, someone decided to mix in milk and add flavors. "And so was born gelato," food historian Francine Segan tells NPR's Audie Cornish.
Of course, people had been making their own take on iced treats much earlier than della Porta's discovery. Some 3,000 years ago, legend has it, people in China used to mix mountain snow, fruit and beer. The Roman Emperor Nero was said to enjoy a drink of honey poured over snow.
In the Middle East, drinks known as the sharbat in Arabic, sharbate in Persian or serbet in Turkish had been popular for ages, Quinzio writes. They were made with sugar and water, citrus like lemons and sweet flowers, and in Persia, they were often served over ice or snow.
Segan says Arabs brought their sharbats to Sicily when they conquered it in the tenth century. "And from those syrups, taking the snow from Mount Etna is Sicily, it evolved into sorbet, or sherbert in English," Segan says.
According to Quinzio's book, a culinary text written by Antonio Latini in the late 1600s includes the first recipe for sorbet recipe written in Italian.
Segan says cookbooks from the 1700s list dozens of floral flavors for iced treats – including rose, violet, lavender and vanilla, which seems to have been forever a popular flavor. Thomas Jefferson is credited with helping to popularize ice cream in America – he fell in love with the treat while serving as a minister in France and began serving it in the President's House (where our nation's leader lived when Philadelphia was the U.S. capital) after his inauguration. A recipe written in Jefferson's hand survives – it calls for two bottles of "good cream," six egg yolks and a half-pound of sugar.
The Virginia Housewife, a cookbook written by Mary Randolph and published in 1824, listed ice cream flavors like apricot and peach. "But then she has some unusual ones like oyster ice cream," Segan says. Think of it as sort of an oyster chowder that's been strained out. She suggested serving it as a first course in hot weather."
In other words, tastes back then were quite adventurous. While we tend to think of savory takes like avocado ice cream as a thoroughly modern spin, "really, this idea of savory and sweet is very ancient," Segan says. "It has been done for centuries."