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Canned Peas
Cook shelled peas in boiling water one half hour. Fill sterilized jars with cooked peas, then pour in cold water until jar will hold no more. Set jars on trivet in boiler, surround jars with cold water, cover boiler, and boil four hours. Seal, and keep in cool place.
This is a boiling-water-bath method for a low-acid vegetable, and it is one of the few historical techniques that modern food science rejects outright. The reasons are specific to peas.
- The pathogenClostridium botulinum spores are common in garden soil and cling to pods and peas. In a sealed jar of moist, low-acid vegetable with no oxygen, those spores germinate and produce botulinum toxin, which is odourless, tasteless and does not swell every jar it spoils.
- Why four hours of boiling is not enoughWater boils at 212F, and botulinum spores are not reliably destroyed at that temperature; extending the boil does not give the dependable margin that modern guidance requires, which is why only a pressure canner, reaching roughly 240F, is accepted for low-acid vegetables.
- Peas are the worst casePeas have a pH around 6.2 and pack densely, so the centre of a filled jar heats slowly and stays a hospitable neutral. Home-canned green beans, corn and peas account for a large share of documented home-canning botulism cases in the twentieth century.
- Cold water and cold packFilling with cold water and starting the jars in cold water would have reduced breakage, but it also means the jars take a considerable time to come up to temperature.
- "Seal, and keep in cool place"Sealing is directed only after processing, so the jars are not sealed during the boil. Cool storage slows spoilage organisms but has no effect on toxin already formed.
- The half-hour pre-boilEven setting safety aside, thirty minutes of boiling followed by four hours in the boiler leaves peas grey, split and mealy. Nothing about the texture recommends the method.
- If you want peas on the shelfUse a current tested procedure from a pressure-canning guide, or freeze them, which suits peas far better. Do not adapt the timings above.
Lowney's book dates from the era when every kitchen was expected to put up the summer garden, and the boiling-water "boiler" or wash-copper was the only equipment most households had. Home pressure canners for domestic use are generally said to have reached households in the early decades of the twentieth century, though the chronology is less tidy than often suggested, and the U.S. Department of Agriculture's warnings against water-bath processing of low-acid vegetables were still being pressed on rural cooks through bulletins and extension agents well into the middle of the century. Recipes like this one were written in good faith on the reasonable-sounding assumption that longer boiling equals greater safety. Commercial canneries of the same period were already using retorts under steam pressure, which is why factory-canned peas were safe when the identical home method was not.Marked as unsafe; the historical text is preserved above unaltered.