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Mushroom Ketchup
Arrange layers of mushrooms and salt in preserving kettle; let stand on back of stove for twelve hours. Press through a sieve. Measure. For each quart of mushroom liquor add one pint vinegar, one tablespoon salt, two tablespoons each of cloves, allspice, mace, and mustard seed. Boil until thick, then bottle. 3 large cucumbers 1 large onion
This is a nineteenth-century preserving formula written for a pantry that expected a certain amount of spoilage. The chemistry it relies on is not sound by current standards, and the notes below explain where it fails as well as what its terms mean.
- Why this one failsMushrooms are a low-acid food, around pH 6, and the recipe dilutes their liquor with only half its volume of vinegar. Even with 5 percent vinegar that lands the finished ketchup near 1.5 to 2 percent acetic acid overall, which is not reliably below the pH 4.6 threshold that prevents Clostridium botulinum from growing in a sealed, oxygen-free bottle. Nothing in the method measures or verifies acidity.
- "Then bottle"There is no processing step at all: no hot-water bath, no timed hold, no headspace, no mention of sterilised jars or of how the closure is sealed. A thick vegetable purée poured warm into a capped bottle and set aside is exactly the condition modern canning guidance is written to prevent. Use a current tested recipe from a food-safety authority if you want mushroom ketchup on a shelf.
- The salt is not a controlThe layering step gives no quantity of salt, and the tablespoon per quart added later is a seasoning, not a preservative concentration. Other period ketchup recipes often specify considerably more salt than this.
- The stray last line"3 large cucumbers 1 large onion" does not belong to this formula; it appears to be the opening of the ingredient list for the recipe that follows, most likely a cucumber relish or ketchup.
- Twelve hours on the back of the stoveThe back of a coal or wood range held a steady warmth somewhere in the range of a very low modern burner. This is a long warm salt extraction to draw the liquor out of the mushrooms, and it also means the purée spends half a day in the temperature band where bacteria multiply fastest before any acid reaches it.
- Spice quantitiesTwo tablespoons each of cloves, allspice, mace and mustard seed per quart is a very heavy hand, and the book does not say whether whole or ground. Many period ketchup recipes call for whole spices bruised and tied in muslin, then lifted out; ground spice at that rate would give a gritty, medicinal result.
Ketchup meant something quite different for most of its English life. The word is generally traced to a Southeast Asian fermented fish or soy sauce, kê-tsiap or the Malay kecap, and eighteenth-century English cooks applied it to any thin, dark, salted, spiced condiment kept in a bottle to sharpen gravies, stews and made dishes. Walnut and mushroom were the standard versions; tomato ketchup was a nineteenth-century latecomer that only became the default in the twentieth. That this recipe survives at all shows how long the older sense of the word persisted in domestic use, and the heavy clove-allspice-mace-mustard spicing is straight out of the English mother recipes that Anglo-American household books had been copying and recopying.