In 1905, according to the Popsicle origin story, an 11-year-old in the San Francisco Bay Area left a cup of soda mixture outside overnight with its stirring stick still inside and found it frozen by morning; 19 years later Frank Epperson patented the “frozen confectionery” as the Epsicle, his children persuaded him to rename it the Popsicle, and the brand says more than 2 billion are now sold each year.

The Popsicle origin story begins with a cup forgotten on a cold California porch. In 1905, 11-year-old Frank Epperson is said to have left a powdered soda drink outside with its stirring stick still in the cup. By morning, the liquid had frozen around the stick, turning an accident into a handheld treat.

The charming part happened overnight; the documented invention took nearly two decades.

Epperson still had to recognise that the idea could be repeated, work out how to manufacture it and protect the process. That distinction matters because the familiar childhood anecdote and the surviving patent record are not the same kind of evidence.

A story preserved by the brand

The Popsicle brand’s history places the episode in the San Francisco Bay Area in 1905. It says Epperson left his cup of soda and its stirring stick on the porch overnight, found the drink frozen, and called the result an “Epsicle.” Later histories usually place the family in Oakland or nearby San Francisco and describe the drink as water mixed with soda powder.

Still, the words “according to the origin story” do real work. There is no surviving childhood notebook, photograph or contemporary newspaper report documenting what the boy found that morning. The National Archives history of the later patent battles says the Popsicle’s birth belongs in legend. Federal court records show that Epperson’s lawyers argued for January 1905 as his date of invention, while competitors disputed how original the idea was.

That does not make the story false. It makes it an origin account remembered and promoted after the product became successful, rather than an event independently recorded at the time.

The patent was for a process, not a childhood memory

The strongest primary evidence is US Patent No. 1,505,592, titled “Frozen confectionery”. It was granted to Frank W. Epperson of Oakland on 19 August 1924 and traces its subject matter through applications filed in 1923 and 1924. The grant therefore came 19 years after the date in the porch story.

The document does not patent the brand name “Epsicle.” It describes a practical method for making a flavoured frozen confection on a handle: fill a smooth cylindrical vessel with syrup, insert a stick almost to the bottom, freeze the contents, loosen the surface and pull out the solid mass by the stick. Epperson suggested ordinary test tubes as moulds and envisioned batches freezing in two to six minutes under intense refrigeration.

Much of the patent reads like an engineer solving small but commercially decisive problems. A non-circular wooden stick would key into the frozen mass more securely. Extending the stick through nearly the full length of the pop would distribute the force used to remove it from the mould. The result could be eaten without a plate, spoon or direct contact between the consumer’s hand and the food.

The chemistry inside an ice pop

A flavoured ice pop is not chemically identical to a block of pure ice. As cooling water molecules organise into crystals, dissolved sugar and flavouring are pushed into the shrinking portion that remains liquid. The American Chemical Society explains that sugar interferes with freezing and lowers the mixture’s freezing point. Food makers can adjust the sugar concentration to help a pop remain solid in the freezer but still be biteable.

The stick works through both geometry and material. Ice expanding into tiny irregularities in the wood helps lock the pop in place, while a long stick supports the frozen mass during removal. Wood is also a poor conductor compared with metal, so it slows heat transfer between the eater’s hand and the confection. The simple handle is simultaneously a support, an insulator and a serving utensil.

Epperson’s patent even anticipated a familiar experience: as the treat is sucked, concentrated flavour can leave first, producing a paler and less flavoursome remnant of ice. That observation follows from the uneven way water and dissolved ingredients behave as the mixture freezes and melts.

From Epsicle to Popsicle

By the early 1920s, Epperson was selling the treats at Neptune Beach, an amusement park in Alameda. The company history says his children urged him to replace “Epsicle” with the name they used at home, “Pop’s ’Sicle.” A Lemelson-MIT profile of Epperson similarly says the children’s nickname became the official name. Details vary between retellings, including whether the early spelling was “Epsicle” or “Eppsicle,” another reason to separate the tidy legend from the paper trail.

The new market was not uncontested. Ice cream entrepreneur Harry Burt had developed a chocolate-coated ice cream bar on a stick and claimed broad patent rights. The court files examined by the National Archives describe years of litigation and licensing, eventually leaving Popsicle associated with water-based ices while Good Humor sold ice cream products on sticks.

Epperson sold his rights to the Joe Lowe Company in 1925, according to MIT’s account. The product expanded nationally, the double-stick version arrived during the Depression, and Unilever acquired the Popsicle brand in 1989. A porch discovery had become an industrial product, a legal asset and a piece of American summer culture.

What the two-billion figure means

Popsicle says more than two billion of its branded ice pops are sold every year. That number comes from the brand itself rather than an independently audited market report, so it is best read as a corporate claim. Even with that caveat, it conveys how far the product travelled from Epperson’s alleged frozen cup.

The story also fits a popular genre of accidental invention, but accidents alone do not create durable technologies. A ScienceBlog account of Percy Spencer and the microwave oven follows the same deeper pattern: a surprising observation became important because someone investigated it, tested it and developed a reproducible system around it.

Whatever precisely happened on that cold night in 1905, Epperson’s lasting contribution was not merely allowing soda to freeze. It was turning frozen flavoured water on a stick into something that could be made consistently, pulled intact from a mould, held comfortably, sold cheaply and recognised everywhere by a name his children supposedly preferred.