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.
In addition, 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.
Home › The Principles of Cookery › Windermere Ketchup
Windermere Ketchup
Procure the largest mushrooms, with broad flaps and red gills, gathered before they are discoloured by the sun. Wipe them with a clean cloth, and break them into an earthen pan. Upon every three handfuls of mushrooms put a handful of salt, so as to form layers, until all the mushrooms are in the pan. Stir them well with a stick or a wooden spoon three or four times a day until the mushrooms are dissolved, which process may be hastened by pressing the several lumps. Now throw the whole into a boiler, and set it over a slow fire, when it must simmer until it is become perfectly liquescent. Strain the hot liquid through a hair sieve, then boil it gently again with some allspice, peppercorns, horse-radish, a few shallots, and two or three bay-leaves. After it has simmered some time, and all the dark scum is taken from it, strain it into a large bottle or jar, which, when the ketchup is quite cold, must be well corked, and a bladder tied over the cork. At the expiration of three months boil it again with a few peppercorns, some fresh allspice, a stick of horse-radish, a few more shallots, and two bay-leaves. Let it simmer half an hour after it has boiled up, then strain it into small bottles; when the ketchup is quite cold, cork the bottles, tie a bladder over the corks, and cover the bladder with sealing-wax. It will then keep any length of time.
This is a fermented mushroom ketchup of the sort that stocked English larders before tomato sauce took the name over. It cannot be reproduced safely, and the reasons are worth spelling out.
- The identification is the fatal problem"Largest mushrooms, with broad flaps and red gills" describes a mature field mushroom, but it equally describes several dangerous species, and gill colour in older specimens is not diagnostic. Amanita and Entoloma species are collected in the same pasture and hedgerow habitats; a single misidentified cap in a three-handful layer contaminates the whole batch.
- Low-acid liquid, sealed and storedMushroom liquor is close to neutral in pH and is a textbook low-acid food. Gentle simmering and a corked bottle sealed under a bladder create exactly the oxygen-free, unacidified conditions in which Clostridium botulinum produces toxin. Nothing in the method reaches the temperature or acidity that would prevent it.
- The three-month intervalThe recipe has the bottle stand sealed for three months at larder temperature before its second boiling. That is a long anaerobic incubation with no measured salt concentration and no acid, and the reboiling at the end is not a reliable safeguard.
- The salt is not a measurement"Upon every three handfuls of mushrooms put a handful of salt" gives no weight and no brine strength. Preservation by salt depends on percentage by weight of the food; a handful ratio can land anywhere, and the cook has no way to know whether the batch is preserved or merely seasoned.
- Bladder and sealing-waxA cleaned animal bladder tied over a cork and waxed was a common nineteenth-century closure for sauces and pickles. It seals closely enough to matter here, which is part of the hazard, and it has no modern equivalent that would make the method sound.
- If you want the flavourCommercial mushroom ketchup is still sold, and current tested recipes for mushroom condiments exist that use cultivated mushrooms and either refrigeration or measured acidification. Use one of those rather than adapting this text.
Ketchup in English cookery long predates tomatoes: the word came into the language in the late seventeenth century, generally traced to a Southeast Asian fermented fish sauce by way of Hokkien or Malay, and was applied in Britain to any thin, dark, long-keeping savoury sauce. Mushroom, walnut and oyster were among the commonest kinds through the eighteenth and nineteenth centuries, mushroom being made in autumn when field mushrooms were abundant and free. Named versions attached to places and estates appear frequently in Victorian recipe collections, and compilations of the period often reprinted them from earlier printed sources, ambiguous mushroom descriptions and all. The double boiling months apart is characteristic of the period's approach to keeping sauces: repeated heating with fresh spice was treated as the mechanism of preservation, since the microbiology that actually governs it was not described until later.