Question arose about ambiguous North American spelling of an old condiment.

In fact it's a phonetic word, evidently imported into English and without
traditional consistent spelling (data below), a situation not uncommon.
(Another example that arose on newsgroups is "recipe" and "receipt,"
pronounced differently today in NA English although "receipt" appears
interchangeably with "recipe" in older cookbooks. A scholar of 18th-century
English advises that they were the same word originally, just different
spellings.) Lacking consistent spelling, people can spell ketchup as they
please, and they do.

As shown below, popular US cookbooks for 200 years normally spelled it
catsup. I seem to remember such spelling as common on tomato-catsup bottles
through about the 1960s, ketchup gradually displacing it (more phonetic, or
a British Invasion? Compare Mrs Beeton below). At the same time, catsups as
a wide class of savory condiments, from various vegetables, fruits, or
seafoods, and normally unsweetened, became eclipsed by commercial tomato
catsup, which also got sweeter. The Hesses in _The Taste of America_
(1977), who by the way spell it ketchup, note that it was widely homemade,
in various flavors, until recent times. They cite OED for the Amoy Chinese
word kétsiap, and say the Malay word kechap may also come from that source.
The Hesses wryly add that a modern US firm developed a bottled ketchup with
natural tomato flavor but it didn't sell, until the product was "slightly
scorched and a metallic component added to give it the taste of 'real'
ketchup." (A comment fairly representative of their book.)

What I found in popular, mostly US, published cookbooks:


Mary Randolph,* 1824 (edition of 1860): "Catsup"

Eliza Leslie, 1837 (edition 1851): "Catchup" (including "Tomata"
tchup.) -- A chapter with eight recipes. Three include wine, one beer.

Mrs Beeton (British, edition 1861): "Ketchup"

Fannie Farmer, 1927: "Catsup"

Morrison Wood (_With A Jug of Wine_), 1949: "Catsup"

Joy of Cooking, 1964: "Catsup"

Fannie Farmer, 1965: "Catsup" (five recipes)


Respectfully submitted -- Max

--
* "Mrs. Randolph freely, perhaps extravagantly, used wines and spirits in
her cooking." -- Janice Longone, The Wine and Food Library, 1993.
Introduction to the Dover reprint of the Mary Randolph book, one of the two
great "best-selling" US cookbooks of 19th century. The other was Eliza
Leslie's.