Important: Safety Warning
This page offers rules for telling edible mushrooms from poisonous ones. No such rules are reliable, and these identifications predate modern mycology. Deadly species closely resemble edible ones, and mistakes are regularly fatal. Never eat a wild mushroom on the strength of this text.
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
Take one-half bushel of freshly gathered mushrooms; wipe them carefully with a damp cloth; put a layer in the bottom of a large stone jar; sprinkle with salt; add more mushrooms and salt until all are used. Let stand over night; mash them and strain off the juice. To every pint add one-half teaspoon of black pepper and one-half dozen whole cloves; put into a preserve kettle and boil slowly until thick. Strain and thin with two tablespoons of vinegar to every pint. Put in bottles and seal.
This is a bottled, sealed, low-acid preserve made from wild-gathered mushrooms, and both halves of that description are why it cannot be reproduced today. The notes below explain the recipe's terms and the specific points at which it fails.
- Why it fails: sealed low-acid bottlesMushroom liquor is close to neutral in pH, and the two tablespoons of vinegar per pint added after boiling are nowhere near enough to acidify it. Sealed in bottles and held at room temperature, that is a textbook anaerobic environment for Clostridium botulinum, whose toxin is among the most lethal known and is not detectable by smell or taste.
- Why it fails: no measured processingThe instruction is simply "put in bottles and seal." There is no jar temperature, no processing time, no headspace and no test of acidity, so nothing in the method controls spore survival. Current USDA home-canning guidance should be followed for any keeping sauce instead.
- Why it fails: wild mushrooms"Freshly gathered" means foraged, and half a bushel is a great deal of material to identify correctly. Several deadly species, notably in the Amanita group, resemble edible field and meadow mushrooms closely enough that experienced pickers have died of the confusion. No printed rule of thumb from this period is reliable.
- Why it fails: unmeasured saltSalt is the recipe's principal preservative, and it is measured by sprinkling. A cure that depends on salt concentration cannot be assessed when the quantity is unknown, and an overnight stand is a short time for salt to draw on whole caps.
- Half a bushelA dry bushel is eight dry gallons, roughly 35 litres; half a bushel of loosely packed mushrooms would weigh somewhere in the region of ten pounds or more, and after mashing and straining would yield only a few pints of juice. The proportions of pepper, cloves and vinegar are given per pint of that strained liquor, not per bushel.
- "Stone jar" and "preserve kettle"A stone jar is a glazed stoneware crock, used because salt and acid attack bare metal. A preserve kettle is a wide, heavy, unlined copper or enamelled pan for open boiling and reduction, not a covered casserole.
- What the dish was forThis is not a table sauce eaten by the spoonful but a dark, intensely savoury seasoning liquid, used a teaspoon at a time in gravies, stews and made dishes. Commercially bottled mushroom ketchup is still sold and serves the same purpose.
Mushroom ketchup is the older English sense of the word: "ketchup" descends from a Southeast Asian term for a fermented fish or shellfish brine, generally traced through Hokkien kê-tsiap, and in eighteenth- and nineteenth-century Britain it named any thin, dark, salty seasoning liquor — walnut, oyster, anchovy or mushroom — long before tomato ketchup became the default. Its function was what a cook now gets from stock concentrate or soy sauce: a shot of savoury depth in gravies and hashes, made from a glut of autumn field mushrooms that would otherwise spoil within days. That it turns up in American household manuals shows how long the English tradition persisted in the United States, and also how casually the period treated sealed bottles of low-acid preserves; the causes of botulism were only being worked out in these same decades, and home-canning guidance built on that science did not reach American kitchens for another generation.