Pickled Salmon
Take a fine fresh salmon, and having cleaned it, cut it into large pieces, and boil it in salted water, as if for eating. Drain it, wipe it with a dry towel, and set it in a cold place until the next day. Then make the pickle in proportion to the quantity of fish. To 1 quart of the water in which the salmon was boiled, allow 2 quarts of good cider vinegar, 1 ounce of whole black pepper, 1 grated nutmeg, and a dozen blades of mace. Boil all of these together in a covered kettle. Remove the kettle from the fire, and when the vinegar has become cold, pour it over the salmon and put a tablespoonful of sweet oil on the top to make it keep longer. Cover closely, put in a cool, dry place. This is a nice way to pickle salmon, and it will keep good for many months.
This is a nineteenth-century keeping recipe, written for a cold larder and a household that expected to eat its way through a whole salmon. The preservation logic behind it does not hold up, and the notes below explain the terms and then why the method fails.
- Why this one cannot be madeCooked fish held for months at larder temperature in a diluted, unmeasured acid is exactly the food and exactly the condition associated with Clostridium botulinum type E, which is native to fish and cold aquatic sediments and grows without oxygen at temperatures well below what most spoilage organisms need. Nothing in the process destroys spores, and nothing verifies the final acidity.
- The vinegar is diluted, not measuredTwo quarts of cider vinegar are cut with one quart of the salted cooking water, and the fish itself carries more moisture into the jar. Period cider vinegar varied widely in strength, so the finished brine has no known pH. Safe acid preservation depends on a measured final acidity, which this recipe never establishes.
- The oil cap makes it worseThe oil cap -- The tablespoon of "sweet oil" (olive oil) floated on top was believed to exclude air and extend keeping. In practice a film of oil encourages the oxygen-free surface conditions in which botulinum can produce toxin, though the closely covered vessel is largely airless in any case. The step offers no real protection.
- "Boil it as if for eating"The salmon is fully cooked, then handled, wiped with a towel, and left overnight in a cold place before the pickle goes on. Cooking removes the fish's competing bacteria while doing nothing to spores, and the overnight rest reintroduces surface contamination onto a food with no barrier left.
- Blades of maceA blade is one strip of the lacy aril that surrounds the nutmeg seed. A dozen blades is a modest quantity, very roughly comparable to a teaspoon of ground mace, though the equivalence is only approximate; the whole blades were used so they could be strained or picked out.
- Sweet oilNineteenth-century shorthand for olive oil. 'Sweet' is usually understood to mean fresh rather than rancid, and the term is also said to have marked edible oil off from lamp oil, train oil and other non-food oils sold alongside it.
- If you want pickled salmonUse a current tested recipe from a food-preservation authority, one that specifies vinegar acidity, curing salt where required, and refrigerated rather than shelf storage. Do not adapt the proportions above.
History: Pickled salmon was a well-established commercial article as well as a domestic one. Through the eighteenth and early nineteenth centuries the Scottish and north-eastern English salmon fisheries shipped boiled, vinegared salmon in kegs to London and beyond, and Newcastle in particular was associated with it; the method let a glut of summer fish reach a market weeks away. Recipes like this one belong to the same tradition in a household form, in the decades before home canning and mechanical refrigeration reached ordinary kitchens. The reliance on a cold larder, a close cover and a film of oil on top is characteristic of the period's preserving instincts: exclude the air, add acid and spice, and trust that a cool dry place will do the rest. The chemistry of anaerobic spoilage was not understood when such recipes were compiled, which is why the very step the writer offers as insurance is the one that makes the jar hazardous.