When people hear that I write about the history and science of food for a living, they often hit me with some variation of the same question: What’s the difference between ketchup and catsup? You probably don’t think much about it, but a bottle of the quintessential American condiment is currently sitting on a refrigerator shelf in 97% of U.S. households. Ketchup may not be top of mind, but it’s a common thread running through most of our lives. So what is the difference, anyway? Semantics, mostly. But to answer the question, we need to travel back in time, and halfway around the world.
Though we closely associate tomatoes with ketchup today – at least here in the U.S. – the condiment’s immediate ancestor is most likely the 16th century homemade fish sauce popularized across large swaths of China at the time. The sauce, which likely originated in China’s coastal Fujian region before spreading north into the mainland, was pronounced ke-chiap. But it’s also possible that Western ketchup instead takes its name and origin from a similar Malay sauce, also made with pickled fish and spices, that spread south into parts of Indonesia. The name of that sauce? Ketjap, kicap, or kecap, depending on how you translate the phonetic sounds into written characters. Both sauces would puzzle ketchup fans today, as they were more akin to dark, rich Worcestershire sauce than any tomato product.
Whichever sauce it was, 17th century European explorers crawling the world in search of spices, preservatives and luxury items came across both variants within a narrow window of time as they established trade routes in the East. By 1690, traders and sailors had brought the first haul of ke-chiap back to Europe. It was an instant sensation, and one that was ultimately called catchup by Europeans who were untrained in the nuanced sounds of the Cantonese language. But when initial supplies had been exhausted, Europeans found themselves lacking in the ingredients necessary to produce the sauce themselves. Ketchup’s first transmogrification had begun.
The English in particular seemed hellbent on producing their own catchup. And they did in the end produce one all their own. Instead of using Chinese spices and fermented fish, English chefs cobbled together disparate ingredients like anchovies, walnuts, oysters, and mushrooms to produce something approximating the original inspiration. Catchup 2.0 was well received, and the word came to mean a mushroom-based sauce for a considerable period of time across the Western world.
The 1711 Charles Lockyer book, An Account of Trade in India, was what cemented the Anglicanized spelling of the word, ketchup. A 1727 reprinting of the book includes a recipe for the sauce that is downright unrecognizable when compared to the labels on today’s bottles of the stuff. Anchovies, shallots, vinegar, white wine, cloves, ginger, mace, nutmeg, pepper and lemon peel combined to form the world’s first published ketchup standard (only the vinegar carries through into today’s best-selling iteration by Heinz). But three years later, a Jonathan Swift poem defied convention by alternatively spelling the sauce, catsup. Both names would stick.
European colonists brought plenty of ketchup along with them as they set up shop in coastal American settlement towns. But crossing the Atlantic was a treacherous, timely affair, and colonists often went years without seeing new supply ships on the horizon. So when the ketchup ran out – the mushroom-based English recipe, for the most part – enterprising colonial cooks tried their hand at recreating the sauce with what precious produce they had at hand in the new world. It’s at this moment that ketchup undergoes it’s next great shift.
Mushrooms were hard to come by in the new metropolises of America. But one new-world crop that farmers mastered with relative ease was the tomato. The 1801 colonial cookbook The Sugar House Book was the first to include a recipe which added the ruby-hued fruit to what was quickly becoming the world’s favorite condiment (in all of its various forms). Sandy Addison’s recipe for ketchup didn’t just flirt with the new addition, it went all in. Calling for 100 tomatoes in her recipe, Addison instructed cooks to “Get (the tomatoes) quite ripe on a dry day, squeeze them with your hands till reduced to a pulp, then put half a pound of fine salt to one hundred tomatoes, and boil them for 2 hours.”
Addison would not live to see her tomato ketchup achieve ubiquitousness. Americans at the time, correctly deducing tomatoes to be a relative of the nightshade family, mistakenly believed the plant to be poisonous. But in 1876 when F & J Heinz tested the waters with the release of its own tomato catsup, the company found attitudes had considerably softened. In the early years of Heinz, the signature product still carried the word tomato in the name, owing to that still being a fairly new take on the Chinese-fish-sauce-turned-English-mushroom-sauce-turned-American-general-store staple. But tomato catsup was a thin, watery condiment better attuned to the task of preserving meats than it was to serving as a dipping sauce.
What we think of as ketchup today is the result not of appetites evolving so much as it was of an entire industry grappling with a government crackdown on a critical food supply-chain item. When the U.S. Food and Drug Administration (FDA) banned catsup’s key preservative ingredient, sodium benzoate, in the early 20th century, Heinz and other ketchup makers scrambled to recreate their secret sauce without it. Though the final product indeed carried a similar name, tomato ketchup now instead of catsup, it was hardly recognizable when compared to its forebear. Where catsup had been thin and salty, made by copiously salting and squeezing unripened tomatoes, the new iteration was thick, viscous, and somewhat sweet, owing to the usage of ripened fruit from here on out. The new tomato ketchup, now just called ketchup, was a hit.
One final tectonic shift in the world of ketchup would come with the spread of World War II across much of the world in the late 1930s. With farmers enlisting in battalions deployed the world over, tomato crops rotted on the vine. The produce that was still being successfully grown was often restricted from general sales, rationed as it was to support the troops. With the world’s biggest tomato growers distracted with war, many countries found it impossible to import bottles of their favorite condiment. But in the Philippines, the spirit of ketchup’s ongoing evolution was in full effect. Here, food manufacturers began producing a banana-based ketchup in the absence of tomatoes. To satisfy consumer expectation, the sauce was dyed red. Even after the war, when tomato production levels spiked once more, this starchy version of the sauce managed to maintain its market share. In many parts of Southeast Asia and Oceania today, banana ketchup remains the default.