DALLAS — This story was originally published on July 11, 2018. It has been updated for this year's 7-Eleven Day.
Dallas has at least one icy concoction on its résumé.
When Mariano Martinez wanted to improve the consistency of the margaritas at his East Dallas Tex-Mex restaurant in the early 1970s, he converted a soft-serve ice cream dispenser into the world's first frozen margarita machine.
But can Dallas also claim the frozen concoction that supposedly inspired Martinez's innovation?
The 7-Eleven Slurpee – which you can get free on Monday (7/11) – was born in 1965, according to the Irving-based company's website. Back then, convenience store chain was owned by the Dallas-based Southland Corporation, which had opened the first 7-Eleven in Oak Cliff.
So 7-Eleven was headquartered in Dallas when the Slurpee made its debut. Simple enough, right?
Because this is highly important, let's explain.
Slurpee is 7-Eleven's brand, trademarked and all, but the actual invention of the icy, sugary treat traces back to 1950s Kansas and a Dairy Queen owner named Omar Knedlik.
Knedlik, the story goes, had a broken soda fountain, so he put bottles of the soda in a freezer to cool them off. When he pulled them out frozen, he served the icy drinks, and they were a hit.
Knedlik then came up with the idea for a machine that would produce the frozen drinks on demand, filing for a patent for the machine in 1958. The patent described the machine's product as a "novel carbonated beverage...involving a liquid and frozen particles and capable of retaining a uniform concentration during melting of the frozen particles."
Knedlik eventually came up with a shorter name for the drink: ICEE.
You can still find ICEEs all over the place, from Target stores to Burger Kings and gas stations. About 500 million ICEEs are sold every year, according to the company.
But while Omar Knedlik had the idea for the ICEE, he didn't build the machine on his own, and that's where Dallas came into play. Knedlik worked on the machine with Dallas-based manufacturer John E. Mitchell, completing it in 1965, according to Smithsonian Magazine.
A 7-Eleven manager in Dallas soon picked up on the "strange new product," according to the National Association of Convenience Stores (NACS). 7-Eleven then bought several ICEE machines and struck a licensing deal with ICEE to sell the slushy product under a different name.
7-Eleven's name for its version of the ICEE was self-explanatory.
"The first time I heard that sound through a straw, it just came out 'slurp,'" Bob Stanford, the director of 7-Eleven's in-house ad agency told NACS. "We added the two e’s to make a noun. It was just a fun name and we decided to go with it."