The first ketchup is centuries old … and very different.
The story of how that red tomato-based sauce made by a company in Pittsburgh ended up in your fridge actually starts with a fish sauce in China. Yes, really. According to
the History Channel, a fish sauce referred to as "ge-thcup" or "koe-cheup" in the local southern Chinese dialect likely served as the starting point for ketchup's long, winding journey to its present form. Though its exact age is hard to pin down, but
some food scholars argue that some version of this type of fish sauce may be more than two millennia old. The sauce that served as a starting point for modern ketchup was effectively a fermented paste derived from fish entrails and soybeans lauded for particularly strong pungence, and ability to hold up over the course of a long journey at sea.
It was precisely that last quality, in addition to its satisfyingly salty taste, that made the condiment an appealing commodity for British sailors along trade routes in southeast Asia. By the 1700s, this fermented fish paste had won enough of them over that they endeavored to bring it back home to England. In a preview of what was to come, the recipe was quickly bastardized, which I guess will happen when you're taking a condiment halfway around the world in the early 18th century. One
contemporary recipe from 1736 called for reproducing the condiment by boiling "two quarts of strong, stale beer and half a pound of anchovies," which is then left to ferment.
In 1800s England, Ketchup was anything you wanted it to be.
Thankfully, ketchup's recipe has evolved from "mix stale beer with anchovies," but not without a circuitous route to its present form. Ketchup had caught on in England (and in the US) by the 19th century, but there wasn't a whole lot of consensus about how it should be made.
As a result, cooks could (and definitely did) make their own take on ketchup derived from all sorts of ingredients that we would hardly associate with the fast food items and backyard cookout staples we douse with ketchup today. We're talking oyster ketchup. Walnut ketchup. Lemon ketchup. Heck, even peach and plum served as the base for a ketchup. Pride and Prejudice author Jane Austen was known to be particularly fond of a certain mushroom ketchup recipe.
While these ketchups were either boiled into a sort of syrup or salted and left to ferment, they usually had something in common: an intensely salty and spicy flavor. It may have been a bit intense on the palate, but its longevity before spoiling certainly helped drive its adoption.