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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Corn in Tins
Remove the corn from the cob and pack uncooked into small tin cans. Put on the lids and solder in such a way as to hermetically seal. Stand these in a wash boiler, cover with cold water. Cover the boiler and place over the fire where the water will come gradually to a boil. Boil continually an hour and a half. Then take a small ice-pick or needle and puncture the centre of each lid. The hole should be like a pinhole. Allow the gases and steam to escape freely, then drop over the hole just one drop of solder. Be sure you have them thoroughly sealed. Continue the boiling two and a half hours. If this process is strictly adhered to according to directions given, not one can in one hundred will be lost. It is far safer than using the glass jars, although even then there is little difficulty with care.
Lima beans and corn may be mixed, boiled until thoroughly done and canned as directed.
This is a home-canning procedure for a low-acid vegetable, carried out entirely at boiling-water temperature in soldered tin cans. It cannot be made safe by adjusting the times, and the equipment itself is a second hazard.
- Corn is low-acid, and that is the whole problemSweet corn sits around pH 6.5-7.0, well above the pH 4.6 threshold below which Clostridium botulinum cannot grow. A sealed can of corn is precisely the oxygen-free, low-acid, moist environment the organism requires.
- Boiling water does not reach the required temperatureWater in an open wash boiler cannot exceed 212F. Botulinum spores can survive prolonged boiling, and destroying them reliably in a low-acid pack requires 240-250F, which only a pressure canner produces. Four hours at 212F is long, hot and still not sufficient.
- The venting step defeats the sealPuncturing each lid mid-process and closing the hole with a drop of solder introduces a deliberate breach in the container. Any organism entering at that moment has hours of warm, sealed incubation ahead of it.
- Solder means leadDomestic and commercial can solder of this period was lead-tin. Lead leaches into food, especially over long boiling and long storage, and there is no acceptable exposure level. Modern food cans are seamed and lined, not soldered, and home canning uses glass with two-piece lids for this reason.
- "Not one can in one hundred will be lost" is the tellThe author's own success rate concedes a one percent failure. With botulism the failed can gives no warning: the toxin is odourless, tasteless and does not necessarily swell or sour the pack. A spoilage rate that would be tolerable for jam is not tolerable here.
- The comparison with glass jars is backwardsThe claim that tins are safer than glass most likely reflects a concern with breakage and leaking seals rather than with pathogens. Glass at least lets you see the contents; neither material addresses the temperature deficit.
- Corn and lima beans togetherThe closing note does not improve matters. Lima beans are also low-acid and dense, and although the recipe has the mixture boiled through before canning, that cooking is still done at boiling-water temperature and does nothing about the spores.
- If you want to put up cornUse a current USDA or extension-service procedure for pressure canning, or simply freeze it. Do not adapt the method above.
Home canning of vegetables in tin was practised in American households in the later nineteenth century, when small cans, solder and cappers could be bought cheaply and some cookbooks gave instructions for soldering cans at home. Corn was a commonly canned crop, since a farm's sweet corn ripens all at once and sours quickly, and the confident tone here presumably reflects a good deal of practical experience: cans were put up this way and eaten without incident often enough for the method to be recommended. What the writer could not know is why the failures failed. Clostridium botulinum was identified in 1895 by van Ermengem from a Belgian outbreak traced to cured ham, but its role in home-canned low-acid vegetables was not widely understood in domestic practice until the 1910s and 1920s, when US Department of Agriculture and state extension bulletins began insisting on pressure processing for anything but fruit and pickles.