Walnut ketchup

What it is

Walnut ketchup is a thin, dark, salty and sharp liquid seasoning. It is not a nut cream or a tomato sauce. The flavour comes from the bitter, astringent juice of young green walnuts, steeped in salt and vinegar, then boiled with spices, shallots, anchovies and wine.

In the eighteenth and nineteenth centuries the word ketchup named many liquid seasonings, and walnut was one of the common forms beside mushroom and tomato. Recipes such as this one were kept by cooks to add depth to gravies, sauces and fish dishes.

Early records

Wikipedia reports that a 1770 manuscript cookbook from Charleston, South Carolina, by Harriott Pinckney Horry contains a walnut ketchup recipe beside a mushroom ketchup. Wikipedia cites Smith (1996) for that manuscript. The same article cites Richard Briggs's The English Art of Cookery, first published in 1788, for both walnut and mushroom ketchup.

Mrs Beeton’s Book of Household Management, first published in 1861, prints a walnut ketchup as recipe 535. Where the 1861 text leaves a gap, modern redactions fill it.

The walnut and the timing

The walnut is the whole question. Pick the walnuts while they are still green, when a pin can still pass through the shell, and to make the ketchup from the beginning to the middle of July. A walnut whose shell has hardened has passed the stage the recipe needs, so the timing is a matter of the nut's maturity as much as the calendar.

The modern redaction on one website keeps the instruction: the walnuts are bruised, left in a jar with salt and vinegar for eight days, and stirred daily. That is the same steep as the 1861 text.

Salt steep and boil

The walnuts are bruised slightly and put into a jar with the salt and vinegar. They stand for eight days and are stirred each day, which draws out the liquor. The liquor is then drained and boiled with the remaining ingredients for about half an hour, so the spices, shallots and anchovies release their flavour into the liquid.

The 1861 text says the result can be strained or not, as preferred, and adjusted with a little more vinegar or wine. It is bottled hot and sealed with corks.

Modern versions

A modern version on another website steeps green walnuts in cider vinegar for ten days, stirring once a day, and then simmers the strained liquid with mace, black pepper, cloves and mirin for about fifteen minutes. That version drops the anchovies and the wine. It is a different product from the 1861 recipe, and its keeping advice is not given.

Both versions are low-acid bottled liquids. The sources do not establish a shelf-stable bottling process, so the storage advice here is the source's own and remains unvalidated.

Using it

Walnut ketchup was used as a seasoning rather than a table sauce. Mrs Beeton's book uses it as an ingredient, for example in walnut gravy and walnut sauce, and in fish sauces. It adds a dark, salty depth to a cooked dish.

Open questions

The 1861 text does not state a yield or a shelf life that a cook can rely on. The walnut's exact maturity is described only by the picking test, and no source gives a measurement for it. John Mollard's cookery book is listed in the catalogue for this subject; its walnut ketchup text was not read for this page and should be added when it is checked.