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Canned Blueberries
6 quarts berries 1 pint sugar 1 cup water Put berries, sugar and water in the preserving kettle; bring to a boil slowly and cook for fifteen minutes.
This is a fragment of a canning method rather than a complete one: it tells you how to cook the fruit and nothing about jars, seals or processing. That gap is the whole problem.
- Why it fails as canningThe recipe assumes the once-standard "open kettle" method — boil the fruit, ladle it into hot jars, clamp the lids and trust the heat of the fruit to sterilise everything. That practice has been abandoned because the jar rim, the lid and the air trapped in the headspace are never held at a reliable temperature, and no processing time or seal check is specified here at all.
- What spoilsBlueberries are acidic enough that botulism is not the main concern; the realistic outcomes are mould, yeast and lactobacillus growth from an incomplete seal, which can be invisible for weeks. A current, tested boiling-water-canning recipe should be used instead.
- The sugar is not a preservative hereOne pint of sugar to six quarts of berries is roughly a tenth of what a preserve or jam carries. This is lightly sweetened stewed fruit, and it depends entirely on the seal for keeping, which the recipe does not provide.
- Fifteen minutes is a long boilEven setting the canning question aside, fifteen minutes at a boil collapses blueberries into a thin purple syrup with the skins floating free. Cooked for the table rather than the shelf, they need only a few minutes to burst.
- Vessel and unitsA "preserving kettle" is a wide, heavy pan — traditionally unlined copper or enamelled ware, stainless steel now. A pint of sugar measured by volume is about 2 cups, roughly 14 oz; the cup of water is only there to keep the fruit from scorching before its own juice runs.
Loose-leaf cookbooks like this one were sold as expandable household systems — pages could be added, rearranged, or replaced as a cook accumulated her own clippings — and in the 1910s and 1920s putting up summer fruit was a domestic obligation rather than a hobby. Blueberries were largely a wild-gathered crop at the time; commercial cultivation of highbush varieties is generally traced to breeding work begun in New Jersey in the first decades of the twentieth century, so a household recipe calling for six quarts at once implies a good picking season rather than a trip to a shop. The bare, telegraphic style here is typical: readers were assumed to already know the jar-filling and sealing routine, which is exactly the knowledge that has since been revised, and why pages like this one now read as incomplete.