Ketchup has come a long way from its Chinese (koe-chiap or tchup) origins as a salted and fermented fish sauce – a thin liquid more like soy sauce. When it eventually found its way to the US and Europe via Asia, it was adapted to suit the local palate and ingredient availability. Variations have included mushroom or walnut sauces and, of course, Worcester sauce.
Later, the addition of tomatoes produced a much thicker liquid – because of the tomatoe’s natural pectin – known as tomato soy. The fermentation cycle was removed to suit the faster manufacturing methods pioneered by the market leading producer. Vinegar and sugar were added, plus starch, to produce the sweet and sour condiment now known to everyone in Europe and the United States as tomato ketchup.