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Tomato Paste
Secure some ripe tomatoes, cut them into quarters and place them in a stewpan with two or three cloves of garlic, a handful of basil and a lump of salt; pour in just enough water to keep them from burning, and stew gently. When cooked turn the tomatoes onto a fine hair-sieve, leave them until all the water has run from them, then pass their pulp through the sieve into a lined saucepan. Season the pulp to taste with pepper and boil it until reduced to a thick paste. It must be stirred constantly with a wooden spoon. When ready turn the paste into small jars, allow it to cool, then tie them over with heavy paper and put them away for future use. This paste makes a very good sauce, and in Italy, where it is used much, it is called conserva.
The technique here is sound Italian practice, but the storage instructions are not. Oscar's paste is a low-acid, unsealed preserve left at room temperature, and the points below explain why that fails by current standards along with what the older kitchen terms mean.
- Why this cannot be stored as directedThe paste is poured warm into jars, covered with paper and "put away for future use" with no processing, no sealed lid, and no refrigeration. Nothing in the method destroys spores or prevents their growth, and paper is not a barrier to mold or airborne contamination.
- Tomatoes are not reliably acidicMany modern tomato varieties sit at or above pH 4.6, the threshold below which Clostridium botulinum cannot grow. Reducing the pulp to a dense paste concentrates sugars and solids but does not acidify it, and the thick, oxygen-poor interior of a jar of paste is precisely the environment the organism favors.
- No measured salt, acid or oilTraditional keeping versions of this preserve rely on heavy salt, a sealing layer of oil, or long sun-drying. "A lump of salt" gives no way to know whether the batch is preserved at all. Use a current tested recipe from a food-safety authority if you want shelf-stable tomato paste.
- "Lined saucepan"In Oscar's day this meant a copper pan lined with tin. The instruction is about avoiding bare copper with acidic fruit, and any nonreactive stainless or enameled pan answers the same purpose.
- Hair sieveA fine sieve of woven horsehair, used for straining and for pushing pulp through. A fine-mesh stainless sieve or a food mill fitted with the fine plate does the identical job.
- The draining step is the pointLetting the cooked tomatoes sit in the sieve until the watery liquid runs off, before working the pulp through, removes much of the moisture before the reduction begins.
- Constant stirring with woodOnce the pulp thickens it catches on the pan bottom quickly. A wooden spoon scrapes the base without scratching a tin lining, and the constant motion is what keeps the paste from scorching.
Conserva — the word means "preserve" — is southern Italian household work rather than restaurant cooking. In Sicily especially, strained tomato pulp was traditionally spread on wooden boards and dried in the sun over several days into a dark, intensely savory paste, known in Sicilian as strattu (estratto), then packed down with salt and oil; Oscar's stovetop reduction reaches a similar end more quickly. The recipe appears in a Waldorf book of 1896, and the text itself still glosses conserva as an Italian term for its readers. The commercial canned tomato paste that made this labor unnecessary in most kitchens came later, and its arrival is a large part of why the recipe reads as unfamiliar now.