Although old cookbook recipes don’t specify what type walnuts they used, they probably used black walnuts, native to eastern North America.
The Persian (English) walnut is native to southwest Asia and southeast Europe. I haven’t been able to determine when the trees first arrived in the U.S., but they tend to grow mostly on the west coast.
Seasonable. Make walnut ketchup from the beginning to the middle of July, when walnuts are in perfection for pickling purposes. You should be able to poke a pin through them. If they’re too hard to do so, you’ve waited too long.
WALNUT KETCHUP RECIPE FROM OLD COOKBOOK
1 handful of salt
1 quart of vinegar
1/4 ounce of mace
1/4 ounce of nutmeg
1/4 ounce of cloves
1/4 ounce of ginger
1/4 ounce of whole black pepper
a small piece of horseradish
1/4 pound of anchovies
1 pint of port wine
MODE: Procure the walnuts when you can run a pin through them. Slightly bruise, and put them into a jar with the salt and vinegar. Let them stand 8 days, stirring every day. Then drain the liquor from them, and boil it with the above ingredients for about one-half hour. It may be strained or not, as preferred, and, if required, a little more vinegar or wine can be added, according to taste. When bottled well, seal the corks.
~~ Have you ever tried walnut ketchup? ~~