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Blackberries Preserved
Allow equal weight of sugar and fruit; place in jars in layers and let stand over night. Juice should not overflow, but if lacking fill up. (Let fruit be three inches from tops.) Cork and wire or screw on tops, letting come to boil in water bath. Let remain five minutes; seal tight and place in cooler spot till cold.
Blackberries and strawberries or pieplant may be put up together.
This is a raw-pack, open-kettle-adjacent preserving method from the era before processing times were standardised, and it cannot be followed safely. The notes below explain the specific failures rather than repairing them.
- The five-minute bath is the central problemThe recipe brings the jars to a boil in the water bath and then holds them only five minutes. That is far shorter than current tested processes for blackberry preserves or canned berries, which are timed from a full rolling boil and adjusted for altitude. The recipe gives no jar size, and raw fruit packed cold with dry sugar heats through slowly.
- Cork and wire is not a sealCork and wire is not a reliable seal -- "Cork and wire or screw on tops" describes pre-1920s closures: a cork held down with wire, or a zinc cap over a rubber ring. A corked-and-wired jar in particular is not a dependable closure, and neither type can be checked for seal failure the way a modern two-piece lid can. The recipe has the tops on before the boil, then calls for a further "seal tight" afterwards.
- Sugar alone will not preserve itEqual weights of sugar and fruit gives a high-sugar syrup, but the sugar dissolves into the berry juice overnight and the finished concentration is unpredictable and generally too low to be self-preserving. The keeping quality here rests entirely on a heat process that is inadequate.
- Spoilage to expectBlackberries, strawberries and rhubarb are all high-acid, so the botulism risk is low; the realistic outcome is mould, yeast fermentation and blown or weeping jars within weeks, sometimes without obvious signs until opened.
- Pieplant"Pieplant" is rhubarb. Only the stalks are edible; the leaves contain oxalic acid in quantity and are toxic, and the original assumes a reader who already knows to discard them.
- "Cooler spot till cold"Most likely this means moving the jars off the heat to finish cooling gradually rather than plunging them anywhere cold; abrupt chilling risks cracking glass jars.
- If you want to make itUse a current tested recipe for blackberry preserves or canned berries from a reliable modern source, or simply freeze the sugared fruit.
Layering fruit with an equal weight of sugar and leaving it overnight is a long-established preserving habit in the English-language kitchen: the sugar draws juice out of the berries by osmosis, so the jar fills with its own syrup and the fruit keeps something closer to its raw shape than boiled jam does. Recipes of this kind proliferated in American household books between the 1870s and the 1910s, when glass jars with wire-and-cork or zinc closures had become cheap enough for ordinary households but processing science had not yet caught up; the USDA and the state agricultural experiment stations only began publishing tested times and temperatures in the 1910s and 1920s, and much of the advice before that was passed along by habit. The casual instruction to combine blackberries with strawberries or pieplant is characteristic of these books, which treated soft fruits as more or less interchangeable in the jar.