“The Iron Lady”, as she was known, was well known for many things: bringing down the Iron Curtain, being the first world leader to embrace Global Warming; but did she really help invent soft serve ice cream? Read on…
It depends on who you believe. The website for The Atlantic had this thoroughly annotated article about her role as a food chemist in the 40’s.
The Iron Lady of Soft Serve. Thatcher, you see, before she was a politician, was a research chemist. The future prime minister, then Margaret Roberts, received a degree in chemistry from Oxford in 1947. And she put it to use first in work at a glue factory, and then with a research job at food manufacturer J. Lyons and Company, a “foodstuff conglomerate” in Hammersmith. Thatcher’s task in that role? To help figure out a way to whip extra air into ice cream using emulsifiers — so that the ice cream could be manufactured with fewer ingredients, thereby reducing production costs. (And so that, additionally, the dairy-y result could flow from a machine rather than being scooped by hand.) While Thatcher’s exact contribution to the effort remains, in a way that would foreshadow her future political career, a matter of controversy, her team ultimately succeeded. And the work resulted, ultimately, in the swirly stuff we know today as soft serve. (Or, if you’re in Britain, “soft scoop.”) J. Lyons’s airy dairy was served from ice cream trucks — under the brand Mr. Whippy — in Great Britain. And then, as soft serve is wont to do, it quickly spread.
But wikipedia claims America invented the soft serve 13 years before a teenaged Iron Lady set foot into the British chemist’s lab:
Over Memorial Day weekend of 1934, Tom Carvel, the founder of the Carvel brand and franchise, suffered a flat tire in his ice cream truck in Hartsdale, New York. He pulled into a parking lot and began selling his melting ice cream to vacationers driving by. Within two days he had sold his entire supply of ice cream and concluded that both a fixed location and soft (as opposed to hard) frozen desserts were potentially good business ideas.  In 1936, Carvel opened his first store on the original broken down truck site and developed a secret soft serve ice cream formula as well as patented super low temperature ice cream machines.
Dairy Queen also claims to have invented soft serve. In 1938, near Moline, Illinois, J.F. McCullough and his son, Alex, developed their soft serve formula. Their first sales experiment was August 4, 1938, in Kankakee, Illinois at the store of their friend, Sherb Noble. Within two hours of the “all you can eat” trial sale, they had dished out more than 1,600 servings (more than one every 4.5 seconds).
So who’s right?
Well, the answer’s tricky, but it seems they all are. While Carvel and McCullough did indeed invent machines the processed ice cream into softer swirls, the British machine was the first to add air, and at least as far as I can research online, the model for modern machines that serve the popular treat today.
Now — there’s also a guy named Kohr, who says he was serving softer ice cream back in 1919. But his was a custard/ice cream hybrid, which may have disqualified him. (or DQ’d him — see what I did there?).
The honest possibility that many people came to many many similar conclusions at or about the same time speaks to a time when word traveled slowly, so if ALL of their combined efforts means I get a sugary treat on a hot day. I salute them all!!