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Canned Plums
Wash and put whole into a syrup made in the proportion of a pint of water and a pound of sugar to every two pounds of fruit; boil for eight minutes, can, and seal immediately. If pricked with a fork before placing in syrup, they will be less liable to burst. Cherries are canned in the same way.
The syrup proportions here are sound and still in use, but the sealing method is the open-kettle technique that every current canning authority has abandoned. The points below explain where this procedure fails and what the original is telling you about the fruit itself.
- Why the method fails"Can, and seal immediately" means filling jars with hot fruit and closing them with no processing in a boiling-water bath. Nothing sterilises the rim, the underside of the lid or the headspace air, and the vacuum that forms as the jar cools is unreliable. A tested current recipe with a measured water-bath time should be used instead.
- What can growPlums and cherries are high-acid, so botulism is not the primary concern; molds and heat-resistant yeasts are. These survive in an unprocessed jar, ferment the syrup, push seals loose and can lower the acidity of the contents over months of storage, at which point the fruit is no longer safe.
- The hardware has changed tooThe recipe does not specify a closure, but jars of the period were typically glass-lidded with rubber rings, or tin-topped and sealed with wax, closed hot and expected to seal as the contents contracted. Modern two-piece lids are designed to vent during processing and cannot be relied on to seal by this method.
- Syrup strengthA pound of sugar to a pint of water is about 2 1/4 cups sugar to 2 cups water, roughly equal parts by weight; by present-day classification that is a very heavy syrup. Two pounds of fruit to that quantity of syrup gives a generous ratio of syrup to fruit.
- Pricking the fruitThis instruction is worth keeping in any context. Plum and cherry skins are tough and largely impermeable; a fork prick or a shallow cut lets the syrup in and the steam out, so the skins do not split and slip off the flesh.
- Eight minutesThe short boil reflects the fruit, not the preservation. A longer boil in syrup softens plums toward sauce, which is why the original time is brief, and it was never long enough to make the jars safe on its own.
The Dixie Cook Book compresses whole categories of fruit into a single formula, as here, where cherries are handed the same treatment as plums in one closing sentence: the assumption is that the cook already understands syrup and jars and needs only the proportions. Open-kettle canning of this kind remained standard advice in American cookbooks well into the twentieth century; the systematic testing that established minimum water-bath times for each fruit and jar size came later, largely through agricultural extension work, and it is that body of measurement, not any change in the fruit, that makes the instruction obsolete. The sugar-heavy syrup is also worth noting as a preservative in its own right, which is part of why these jars kept as well as they did despite the method.