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Canned Tomatoes
Remove skins from tomatoes; boil hard twenty minutes; fill sterilized jars, being careful to keep seeds away from rubbers. Seal, and keep in cool place.
This is open-kettle canning: food boiled in a pot, ladled hot into jars, sealed, and set aside with no processing after sealing. It was standard practice in 1907 and has been rejected by every food-safety authority since. The notes below explain the specific failures rather than offering a fix.
- No processing after sealingNothing here heats the sealed jar. The contents are boiled in the open kettle, then transferred, so the jar rim, the underside of the lid and the headspace air are never sterilized and the seal is formed by cooling rather than by a verified vacuum. Contamination introduced during the transfer is sealed in with the food.
- Tomatoes sit on the acidity borderlineSafe unprocessed sealing depends on the food being reliably acid. Tomatoes cluster close to pH 4.6, the accepted dividing line between acid and low-acid foods, and some fruit falls on the wrong side of it depending on variety, ripeness and whether any overripe or frost-touched tomatoes went into the pot. Current practice requires measured added acid — bottled lemon juice or citric acid in a stated amount per jar — precisely because the fruit itself cannot be trusted to fall on the safe side.
- Twenty minutes of boiling does not sterilizeClostridium botulinum spores survive hours at 212F. Boiling kills the vegetative bacteria and yeasts that would spoil the tomatoes visibly; it leaves the spores that produce botulinum toxin in a sealed, oxygen-free, low-acid jar. The result can look, smell and sound perfectly sound and still be lethal.
- "Cool place" is not a controlThe recipe's only safeguard after sealing is storage temperature, and an early-twentieth-century cellar was neither cold nor consistent. Botulinum grows well at ordinary room and cellar temperatures.
- The hardware is obsoleteThe "rubbers" are the red rubber rings used with glass-lidded jars and zinc caps. Those closures cannot be checked for a proper vacuum the way a modern two-piece lid can, and the rings hardened and failed with age — which is why the recipe warns about seeds fouling the sealing surface.
- If you want canned tomatoesUse a current tested procedure from a food-preservation extension service, with measured added acid and a full boiling-water or pressure process timed for your jar size and altitude. Home-canned tomatoes remain entirely practical; this method is not the way to get there.
Lowney's Cook Book was compiled by Maria Willett Howard for the Walter M. Lowney Company, a Boston chocolate manufacturer, and like other branded cookbooks of its era it surrounded the confectionery with a full household repertoire — including a preserving chapter, at a time when many kitchens still put up their own tomatoes. The open-kettle method described here was widely used, and the terseness of the instructions suggests how routine it was: the only detail thought worth spelling out is keeping seeds off the rubber ring, since a seed under the gasket could mean a failed seal and a spoiled jar. Systematic research into home canning followed over the next two decades, and by the 1920s American extension bulletins were pushing processing in the sealed jar and warning against open-kettle work for anything but high-sugar jams and jellies. Tomatoes, sitting close to the edge of the acid range, turned out to be a particularly poor candidate for the old shortcut.