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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Mushrooms Pickled in Brine
Prepare button mushrooms precisely as directed in the preceding recipe, but make a brine as follows. Boil together two quarts of water, eight ounces of salt, three small blades of mace, an ounce or more of bruised ginger, and the same of whole white pepper. Skim while boiling, add the prepared button mushrooms, and boil slowly for a few minutes. Fill well-dried bottles while the mushrooms are still hot, and when quite cold cork the bottles, and tie down with skin. A small quantity of salad-oil poured on the top of each bottle will effectually preserve the contents.
This is a preserving method, not a same-day pickle, and it fails on every point that modern food safety turns on. The notes below explain where the danger lies rather than how to rescue it.
- No acid at allDespite the word "pickled," there is no vinegar or other acid here — only salt. Mushrooms are a low-acid food, well above pH 4.6, and acidity is the main barrier that keeps Clostridium botulinum from growing in a sealed jar; without it, safety depends entirely on the heat process and on salt levels this brine does not reach.
- The brine is far too weak to preserveEight ounces of salt in two quarts of water is roughly an 11 to 12 percent brine before the mushrooms are added, and mushrooms are around 90 percent water, so the finished strength drops well below that — and below the concentration that would inhibit bacterial growth in a sealed, unrefrigerated container.
- "Boil slowly for a few minutes" is not a processA brief boil kills vegetative bacteria and moulds but does little to botulinum spores, which can survive hours at boiling point. Low-acid foods require a pressure canner at 240°F — a domestic appliance, and the bacteriological rationale for it, that were not available when this book was compiled.
- The oil seal is the worst partA film of salad oil poured on top creates exactly the oxygen-free layer botulinum needs. Mushrooms under oil have been implicated in real botulism outbreaks in the modern era; this is not a theoretical hazard.
- Corked and tied with skinBladder or parchment tied over a cork gives no hermetic seal and no vacuum. Spoilage in such a bottle may be invisible and odourless — botulinum toxin need not announce itself by smell, taste or gas.
- If you want preserved mushroomsUse a current tested recipe: either a properly acidified vinegar pickle stored in the refrigerator, or a pressure-canned pack following USDA process times. Do not adapt the proportions above.
- Reading the ingredients historicallyA blade of mace is one strip of the lacy aril around a nutmeg; "bruised ginger" in recipes of this period generally means whole dried root cracked with the flat of a knife rather than fresh. Both are aromatics rather than preservatives and contribute nothing meaningful to safety.
Bottling mushrooms in salt water sat alongside ketchup, powder and pickle as one of the standard Victorian ways of stretching a short, unpredictable season — button mushrooms appeared in quantity for a few weeks and then vanished. Cassell's presents this in a run of preserving recipes that all rest on the same pre-bacteriological assumptions: that heat drives out whatever causes decay, that salt and spice discourage its return, and that excluding air with a layer of fat or oil finishes the job. That last idea, oil as a sealant, was ancient and widely trusted; it is also precisely the condition under which the botulinum organism thrives, an illness German physicians had been calling Wurstvergiftung, sausage poisoning. Recipes like this one are a useful reminder that the Victorian storeroom was a riskier place than its confident prose suggests.