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Chicken Broth
Cut a fowl in joints as for a fricassée, cover with boiling water, and let boil ten minutes, then simmer until the chicken is tender. Have ready a pint or a quart jar sterilized in the usual manner, and pour into it broth, boiling hot, to fill it to overflow; adjust the rubber ring and sterilized cover and tighten at once. Often when cooking a four or five pound fowl, a can of broth may be set aside without detriment to the service of the fowl.
The broth-making itself is unremarkable; the canning method is the problem. This is open-kettle canning of a low-acid food, a practice abandoned by food-safety authorities roughly a century ago.
- Why this one failsChicken broth sits around pH 6 to 7, well above the 4.6 threshold below which Clostridium botulinum cannot grow. A sealed jar of broth at room temperature is close to an ideal anaerobic incubator for it.
- Boiling does not sterilizeThe recipe relies on the broth being "boiling hot" to sterilize the jar and its contents. Botulinum spores can survive hours at 212F; destroying them reliably in a sealed jar requires 240F or above, which only a pressure canner reaches. No amount of extra simmering on the stovetop substitutes.
- No processing step at allThere is no time in a canner given, because there is no canner. The jar is filled, capped and set aside. Even the boiling-water-bath times printed elsewhere in books of this era would be inadequate for plain meat broth.
- The seal proves nothingHot liquid capped and tightened will cool and pull a vacuum, so the jar looks and sounds correctly sealed. A firm seal on an unprocessed low-acid jar is evidence of nothing but contraction, and botulinum toxin gives no reliable warning in smell, appearance or taste.
- Rubber rings and zinc capsRubber rings and separate covers -- The rubber ring and separate sterilized cover belong to a jar system no longer manufactured for canning. Modern two-piece lids are also not meant to be fully tightened before processing, which is a further reason the instructions do not map onto current equipment.
- A "fowl"In books of this period the word means a mature bird rather than a young one, tougher and generally stronger in flavour than a supermarket broiler, which is why the original expects a long simmer to tenderness. It does not make the canning method viable.
- If you want shelf-stable brothFollow a current tested pressure-canning procedure with specified pressures and times for your altitude, or set the question aside and refrigerate or freeze the broth instead.
"Open-kettle" canning — cook the food, pour it boiling into a sterilized jar, seal, and trust the heat of the food itself — was a common domestic method through the nineteenth century and into the early twentieth, and it works passably for jams and pickles, where sugar and acid do the preserving work the heat did not. Applied to meat, broth, corn or beans it was dangerous. Clostridium botulinum was first identified in 1895, but its association with home-canned low-acid foods in the United States was not firmly established until investigations in the 1910s and 1920s; pressure canners and tested processing tables from federal and land-grant extension work reshaped home canning in the following decades. The last line, about setting aside a jar of broth from a fowl already destined for the table, reflects the thrift of the book. That is worth keeping. The method is not.