The origins of ketchup – or catsup – run through ... fish sauce?

Like many Americans, I dip my french fries in ketchup. Or is it catsup? As a condiment and as a word, ketchup has an interesting history.

I had thought that ketchup was the corn-syrupy sauce beloved by children and scorned by gastronomes, while catsup was the original, more sophisticated version. It turns out that in name, at least, ketchup is actually closer to the sauce that inspired it. According to food writer Stephanie Butler, this sauce was first made around 300 B.C., in southern China. Taste-wise it was apparently nothing like America’s favorite fry topping, being a fermented paste “made from fish entrails, meat byproducts and soybeans,” but its name looks similar: kê-chiap, kôe-tsap, or kôe-chiap. The Oxford English Dictionary explains that in dialects of Hokkien, a language of the area, kôe is a kind of fish, and chiap means “juice, sauce.” Our tomato-based, sugary ketchup is, literally, “fish juice.”

Ketchup spread widely along maritime trade routes, and British sailors encountered it, loved it, and brought it back home in the late 17th century. The 18th century was “a golden age for ketchup,” as Ms. Butler relates – there were versions made from oysters, mushrooms, walnuts, mussels, and even fruit. The Prince of Wales’ ketchup, for example, was a delicious – I guess – combination of elderberries and anchovies. What unified these different ingredients into “ketchup” was the way they were processed – they were mixed with vinegar or other acidic liquids and boiled down to a syrupy consistency, making an intensely flavored sauce.    

Since the English word was a phonetic rendering of sounds from dialects of Hokkien, its early spellings were as various as the condiment’s ingredients, though ketchup predominated: kitchup, catchup, katchop, catchop, catshup, and so on. The sauce, as the author of an 1831 cookbook quipped, “can be pronounced by every body but spelled by nobody.” Catsup had possessed extra cachet since at least 1730, when satirist Jonathan Swift included it in a list of dodgy foreign indulgences (as opposed to “wholesome” English bread and cheese).

When commercial ketchup production began, tomatoes edged out other flavor bases. In Britain, ketchup overtook catsup as the most frequently used name around 1850, but in the U.S., catsup held on to its dominance until the 1980s.

Today chefs are once again experimenting, and you can find recipes for tomatillo, blueberry-chipotle, and banana ketchup (popular in the Philippines) online. In the U.S., these condiments cannot be sold as “ketchup” (or catsup or catchup), however, since according to American law, the main ingredient of ketchup is tomatoes – nothing else.