Important: Safety Warning
This page describes home-canning methods from before the causes of botulism were understood. Canning low-acid foods without a pressure canner, as described here, can allow the growth of Clostridium botulinum, whose toxin is among the deadliest known. Follow current USDA home-canning guidelines instead.
This information has been left in for historical purposes but should not be acted upon.
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Mushroom Catsup
1 pint mushroom liquor 1/2 ounce peppercorns 1/4 ounce allspice Salt 1/4 ounce green ginger root 1/4 ounce cloves 1 blade mace Wash and look over the mushrooms carefully; put them in an earthen jar with alternate layers of salt. Let stand for twentyfour hours in a comparatively warm place; put through a fruit press and add the ginger root cut into small pieces. Measure the liquor; add peppercorns and simmer for forty minutes; then add the spices and boil for fifteen minutes. Take from the fire and cool. Strain through a cloth; bottle and seal.
This is a salt-extracted mushroom liquor, boiled with spices and sealed hot in bottles. The method belongs to an era before the botulism hazard of low-acid preserves was understood, and the quantities here put it outside any safe modern practice.
- Why this one failsMushrooms are a low-acid food, and this catsup contains no vinegar or other added acid at all. Sealing a boiled, low-acid liquid into bottles creates exactly the warm, oxygen-poor environment in which Clostridium botulinum spores germinate and produce toxin. Boiling for fifteen minutes kills vegetative bacteria but not the spores.
- The salt is unmeasuredSalt is the only preservative in the formula and the recipe gives no quantity for it — just "alternate layers." A cure that depends entirely on salt concentration cannot be assessed, let alone reproduced, when the concentration is unknown.
- Twenty-four hours in a warm placeThe mushrooms are deliberately held in a "comparatively warm place" before any heat is applied. That step is what draws out the liquor; no temperature is specified, and any microbial activity during it is uncontrolled.
- "Bottle and seal" is not a processThere is no processing time, no headspace, no jar or closure specified, and no indication of whether the sealed bottles are meant to be stored cool. Modern guidelines for any shelf-stable low-acid product require measured pressure-canner processing.
- Wild mushrooms"Wash and look over the mushrooms carefully" may point to a reader gathering field mushrooms rather than buying cultivated ones; the recipe does not say. If wild mushrooms are used, misidentification is a separate and serious risk that no amount of boiling or salting corrects.
- If you want mushroom ketchupUse a current recipe from a tested source — a vinegar-based version kept refrigerated, or one processed to USDA guidelines.
Mushroom catsup is the older sense of the word: before tomatoes took over the name in the nineteenth century, "catsup" or "ketchup" meant a thin, dark, salty brown liquid used the way we now use Worcestershire or soy — a few spoonfuls stirred into gravies, stews and made dishes to deepen them. English cookery books of the eighteenth and nineteenth centuries carry many versions, usually built on salted mushrooms, walnuts or anchovies, and the word itself is generally traced to a Southeast Asian fermented fish sauce term borrowed through Dutch and English traders. A mushroom glut drawn down to a pint of concentrated liquor and spiced with peppercorns, cloves, mace, allspice and green ginger was a way of keeping flavour on the shelf. The book offers no processing instructions at all beyond "bottle and seal."