At the same time that Americans are demanding more fresh foods and a return to ingredients that our grandparents might recognize, processed food Campbell’s looked back at its own heritage and decided to conduct an experiment, remaking the company’s original tomato soup recipe from 1915.

Fortune took a trip (warning: auto-play video at that link) to the factory where the company’s current soups are made to learn more about this exercise in retro cookery, and how it fits in with current food trends.

The old recipe makes 10,000 jars of beefsteak tomato soup, which is small-batch production as far as Campbell’s is concerned. The company sells 85 million cans of its modern condensed tomato soup every year, but took on the 1915 recipe project as a special project to ponder the nature of packaged food as well as a publicity stunt.

The recipe they followed was devised by chemist and former company president Dr. John Dorrance. While Dorrance invented the company’s original methods for condensing soups, the beefsteak tomato soup from 1915 was a ready-to-serve version.

You’d think that a recipe is a recipe, but methods have changed over the decades, and so has the equipment available in the factory. The recipe called for beefsteak tomatoes grown in New Jersey, while the familiar modern tomato soup uses tomatoes shipped in from California.

The team knew what a New Jersey-grown tomato was, but other items in the recipe were confusing or lost to history, like the ingredient measured in a “#16 bucket.” Retirees who had been with the company for decades were able to help with some questions of cooking methods and bucket sizes.

The 1915 version did have a lot of the original food preservative: salt. “[The recipe] was very salty,” a member of the company’s R&D team told Fortune. “I think that is just what they liked.”

They adjusted the salt levels for modern palates, because the soup wasn’t just a fun experiment: it will be available for sale. You’ll be able to buy jars at Cracker Barrel restaurants in New Jersey and Pennsylvania, near the factory where the soup was made.

By the way, it just so happens that Campbell’s is launching a new line of refrigerated organic soups called Souplicity. We’re sure that’s 100% unrelated to all of this old-timey recipe revival, though it’s notable that you don’t see the Campbell’s name on the Souplicity web page.

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