Ketchup did not start out as a tomato sauce. Most historians and linguists agree that the word, and the idea, came from a fermented fish sauce made by Hokkien-speaking communities in southern China and across Southeast Asia, called something like kê-tsiap. British traders came across these salty, savoury sauces in the late seventeenth century and took the name home. For well over a century after that, "ketchup" in England meant a thin, dark seasoning made from anchovies, mushrooms or walnuts. Tomatoes only arrived in the early 1800s, in America. The sweet red bottle is the newest chapter of a very long story.
A sauce made from fish, salt and time
Picture a harbour on the South China Sea in the 1600s. Small fish are packed in salt and left in jars until the flesh breaks down into a pungent, amber liquid. Sauces like this were everyday seasonings across the region, from Fujian to Vietnam, and they still are. In much of Southeast Asia, fish sauce is as basic to the kitchen as salt is in Europe.
In Hokkien, the language of southern Fujian, one such sauce had a name usually written today as kê-tsiap, which means roughly "preserved-fish sauce". Hokkien merchants had settled in trading ports all over Southeast Asia, and that seems to be where European traders, the British among them, first met it. The linguist Dan Jurafsky brought this account to a wide audience in his book The Language of Food, and it is the one most dictionaries now give.
Some trace the word's route into English through Malay. In Indonesia, kecap still means a soy-based sauce, such as the sweet, treacly kecap manis. Exactly which sauce, and which port, will probably never be pinned down, but historians broadly agree that ketchup started with fish.
England falls for a name
By the end of the seventeenth century the word had reached English, and nobody could agree how to spell it: catchup, catsup, katchup. English cooks had the name but not the sauce, so they imitated it with what they had.
They wanted a strong, savoury liquid that kept well and could lift a gravy or a stew with a single spoonful. One early printed recipe, in Eliza Smith's The Compleat Housewife of 1727, makes its "katchup" from anchovies, shallots, wine vinegar and spices, which is not far from the spirit of the original. Over the eighteenth century, English cookery books filled up with other versions. Mushroom ketchup was made by salting mushrooms until they gave up their dark juices. Walnut ketchup used green walnuts picked before the shells had hardened. There was oyster ketchup too.
None of these were red, and none were sweet. They were more like what we now call Worcestershire sauce or soy sauce: thin, brown, salty and very savoury, kept in the larder and shaken into dishes. Mushroom ketchup is still sold in Britain today.
Enter the tomato
Tomatoes came to Europe from the Americas in the sixteenth century, but in Britain and North America people were wary of them for a long time, and many grew them as a curiosity rather than as food. By the early nineteenth century that was changing, and tomatoes began to go into the ketchup pot.
The earliest known published recipe for tomato ketchup is usually credited to James Mease, a Philadelphia physician with a keen interest in plants, in 1812. He called the fruit by its old name, "love apples". Early tomato ketchups were thin and heavily spiced, and many did not keep well. As bottled ketchup became big business in the United States during the nineteenth century, some manufacturers cut corners with poor ingredients and chemical preservatives.
The best-known name in the story is Henry J. Heinz of Pittsburgh, who added tomato ketchup to his range in 1876. In the early twentieth century, Americans were arguing fiercely about preservatives in food, and Heinz championed a ketchup that kept without the preservative sodium benzoate. The usual account is that it relied on ripe tomatoes and a good deal more vinegar and sugar. That thicker, sweeter, tangier sauce became the model for ketchup almost everywhere.
Why the fish and the tomato are closer than they look
You could call modern ketchup a sweet betrayal of its salty ancestor, and in one sense it is. But the whole story runs on a hunger for savoury depth. Fermented fish sauce is rich in glutamates, the compounds behind the taste we call umami. So are ripe tomatoes, especially cooked down, and so are mushrooms and anchovies. Whether they worked in Fujian, in a Georgian kitchen or in a Pittsburgh factory, every ketchup maker was after the same thing: a spoonful that makes other food taste more like itself.
A better ketchup at home
Homemade ketchup is less sweet, more tomatoey and far more interesting than most bottles. It takes about an hour, and most of that is gentle simmering.
- Start with good tomatoes. Out of season, tinned plum tomatoes or passata with a spoonful of tomato purée beat pale fresh ones. In late summer, roast ripe tomatoes first for a sweeter, deeper base.
- Soften the aromatics. Cook a chopped onion and a little garlic slowly in oil until soft and sweet before the tomatoes go in.
- Use the old ketchup spices. A pinch each of ground allspice, clove and cinnamon, a bay leaf and a little celery or mustard seed give the familiar warm background. Go lightly, because you can add more spice later but you cannot take it out.
- Balance sweet and sour at the end. Add cider or wine vinegar and a modest amount of sugar, simmer, then taste and adjust. It should taste tangy first and sweet second.
- Nod to the ancestor. A few drops of fish sauce, a mashed anchovy fillet or a dash of Worcestershire sauce add a savoury depth that nobody can quite name. For a vegetarian version, use soy sauce.
- Reduce, then blend. Simmer uncovered, stirring more often as it thickens, until it coats a spoon. Blend it smooth and push it through a sieve for a glossy finish. It thickens further as it cools.
- Store it sensibly. Pour it into a clean, sterilised jar, keep it in the fridge and use it within about two weeks.
Less sugar, same tang
Shop-bought ketchup is often surprisingly sweet. The Keto and Low-Carb Kitchen has its own Keto Ketchup and a smoky Sugar-Free Barbecue Sauce, and both go well with the Bunless Bacon Cheeseburgers and a tray of Celeriac Chips. Our guide to low-carb swaps that keep the flavour has more ideas along the same lines, and you can browse every sauce in the recipe finder.
Questions people ask
Is ketchup originally Chinese?
Probably, or more precisely Hokkien. The most widely accepted account links the word to kê-tsiap, a fermented fish sauce from southern China that Hokkien communities also made across Southeast Asia. Tomato ketchup is an American development.
What was ketchup originally made from?
Fish and salt, fermented. In Britain, early ketchups were made from anchovies, mushrooms, walnuts or oysters. Tomato ketchup did not appear until the nineteenth century.
When was tomato ketchup invented?
The earliest known published recipe is usually dated to 1812 and credited to James Mease of Philadelphia. Heinz began selling tomato ketchup in 1876. Its sweeter recipe without preservatives, from the early twentieth century, shaped the ketchup most people know today.
Why is ketchup sometimes called catsup?
English speakers spelled the borrowed word in several ways from the start, including catchup and catsup. Ketchup eventually won, but catsup survived, especially in the United States.