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Plums (Usually canned without)
Plums are usually canned without removing the skins. Prick each plum in several places that the skin may not burst. Wash and drain the plums. Allow a cup of sugar to each quart of plums and about a cup of water to four quarts of plums. Make a syrup of the sugar and water, put in part of the plums, let cook about five minutes, skim into jars, fill the jars with the boiling syrup, and seal at once. Reheat the syrup to the boiling point, add the rest of the plums, cook and seal as before.
This is open-kettle canning: hot fruit ladled into jars, topped with boiling syrup, and sealed with no further processing. That method was standard in 1900 and has been rejected by every current canning authority since, so the notes below explain the method rather than adapt it.
- Why the seal is the problemNothing sterilises the jar rim, the underside of the lid, or the headspace air once the jar is closed. Yeasts, molds and heat-resistant spoilage organisms introduced during filling can survive, and the vacuum formed by cooling is unreliable — jars sealed this way may unseal later on the shelf.
- No processing time or temperature at allThe recipe gives five minutes in syrup and then "seal at once." There is no measured heat treatment of the filled, closed jar, which is the step that current tested procedures depend on. Without it there is no way to know whether a given batch is shelf-stable.
- The acidity does not rescue itPlums are genuinely acid fruit, which makes Clostridium botulinum growth unlikely, so this is not the same hazard as open-kettle beans or corn. What it does invite is mold and yeast spoilage, and some molds on stored fruit produce mycotoxins — a fermented, fizzing or fuzzy jar of plums must be discarded, not skimmed and re-boiled.
- Jars and closures have changedJars of this period were commonly glass-lidded or bail-type closures sealed with rubber rings, though this recipe does not specify any. Modern two-piece lids are designed around a measured processing step and may not seal predictably if simply screwed onto boiling fruit.
- What the syrup ratio tells youOne cup of sugar per quart of plums and one cup of water per four quarts is a thin syrup by modern standards. Sugar here is for flavour and texture, not preservation, and at this concentration it contributes nothing to keeping quality.
- The pricking is soundPiercing each plum in several places is still the right technique for whole unpeeled stone fruit — it lets the skin equalise pressure instead of splitting, and helps syrup penetrate. That detail is worth carrying over to a current recipe.
- Use a tested procedure insteadWhole or halved plums in syrup are covered by every modern canning guide with specific headspace, boiling-water-bath times and altitude adjustments. Follow one of those rather than this text.
Open-kettle canning dominated American home preserving from the mid-nineteenth century until well into the twentieth, and books of this era present it as simply how fruit was put up: cook it, pack it boiling hot, close the jar, and trust the heat of the contents to do the rest. It worked often enough with acid fruits like plums, cherries and rhubarb to keep the method in use. Extension services and the USDA began pressing for boiling-water processing of all canned fruit as home-economics research put numbers to what had been guesswork, and open-kettle canning was formally condemned in later federal guidance. The recipe's instruction to work in two batches, reheating the syrup between them, is given without explanation.