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Tomatoes, Preserved
Cut the tomatoes into pieces, and simmer them gently over a slow fire till they are reduced to a pulp. Squeeze the juice from this pulp, boil it until it is as thick as cream, and then pour it into small bottles. Place these in a large boiler with cold water up to their necks. Bring the water to the boil, and let it boil for a quarter of an hour, then lift the bottles from the fire, and let them remain in the water till it is cold. Cork securely, and wax the corks. Store in a cool, dry place. Time to boil, a quarter of an hour.
This is a nineteenth-century method for bottling tomato pulp, and it fails on every point that modern preserving practice treats as essential. The notes below explain where, rather than how to fix it.
- The seal is made after the heat, not by itThe bottles are processed uncorked, cooled in the water, and only then corked and waxed. Nothing sterile is sealed in; the cooling headspace draws in room air and whatever it carries, and wax over a cork is not an airtight closure. There is no vacuum and no evidence of one, so a failed jar cannot be identified before it is opened.
- Botulism is the specific riskClostridium botulinum spores survive boiling-water temperatures and germinate in sealed, oxygen-free food that is not acidic enough. Cooked-down tomato pulp in a stoppered bottle at room temperature can provide those conditions, and the toxin gives no smell, taste or visible sign.
- Tomatoes are not reliably acidicModern tomato varieties sit on the borderline of pH 4.6, the line below which boiling-water processing is considered adequate. Current guidance requires measured added acid — bottled lemon juice or citric acid at a stated rate per jar — for every batch of plain tomatoes. This recipe adds none, and reducing the pulp cannot be relied on to bring its pH down to a safe level.
- A quarter of an hour is not a process timeFifteen minutes is given for bottles of unspecified size, starting from cold water, with no jar type, headspace or altitude adjustment named. Real process times are set for a defined container and a defined product density; thick, reduced purée heats far more slowly than juice.
- "A cool, dry place" was the whole safeguardStorage was expected to do much of the work -- Beyond the quarter-hour boil, the only safeguard named is a cool, dry place. Period bottling generally aimed to slow spoilage by keeping food cold rather than by destroying spores, which were not yet known. Household storage temperatures today are often higher, which removes even that partial protection.
- What the method does showThe technique itself — slow reduction of tomato pulp and its strained juice until it thickens — is sound cooking, and reduction of this kind is still how tomato paste is made. It is the preservation and storage that are obsolete. For keeping it, freeze it, or follow a current tested recipe from a reputable preserving authority.
This is a nineteenth-century domestic bottling method, from a period when the tomato was becoming a more familiar British ingredient rather than a curiosity of the glasshouse and the Italian grocer. Bottling was an ordinary domestic answer to a glut: fruit and pulp were cooked down, put into whatever bottles the house had, heated in a boiler, and stoppered with cork and wax, the same closure used for beer and sauce. The general principle of heating food in sealed vessels goes back to Nicolas Appert's work early in the nineteenth century, and it spread through household manuals long before anyone understood microbes, let alone heat-resistant spores. What the period could not know is that heat and airtightness are not interchangeable, and that a food's acidity determines how much heat is enough — a distinction that became standard advice only in the twentieth century.