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Shrimps, Potted Whole
Put a pint of freshly-boiled and shelled shrimps into a dish, and sprinkle over them half a tea-spoonful of salt, a tea-spoonful of white pepper, and a pinch of grated nutmeg. Put an ounce of butter in little pieces here and there upon them, and place the dish in a moderate oven till the butter is melted. Let the shrimps get cold. Press them into jars, and pour upon them butter which has been melted, and is just beginning to set. Keep the jars in a cool place till wanted. Time to bake the shrimps, ten minutes.
Potting under a butter seal was a preservation method, and that is exactly where this recipe fails. The problems are in the storage, not the seasoning.
- The butter seal is the hazardClarified or melted butter poured over cooked shellfish creates an oxygen-free layer over a low-acid, high-moisture food. That is the precise condition in which Clostridium botulinum spores germinate and produce toxin, and the spores survive the ten minutes in a moderate oven that this recipe calls for.
- "A cool place" is not a temperatureA Victorian larder had no fixed temperature and would have varied widely with the season. Non-proteolytic strains of C. botulinum can grow at temperatures as low as 38F, and the recipe gives no keeping time at all, so there is no way to read a safe window into it.
- No acid, no cure, no measured saltHalf a teaspoon of salt to a pint of shrimps is a seasoning quantity, not a preserving one. There is no vinegar, no nitrite, no water activity control of any kind — nothing in the formula does the work the butter is being asked to do.
- Spoilage gives no warningBotulinum toxin does not sour, gas or smell in the way ordinary spoilage does, and potted shellfish is eaten cold and unheated. There is no step at which a cook would catch the problem.
- If you want potted shrimpsUse a current recipe with stated refrigeration and a stated keeping time. Potted shrimps are still made commercially and domestically, but as a short-life chilled dish rather than a stored one.
- Reading the originalA pint of shelled shrimps is a volume measure, not a weight, and the recipe does not say which shrimp is meant, though small shrimps rather than large prawns are the likely intent. The book gives no oven temperatures; "a moderate oven" is conventionally read today as somewhere around 350F.
Potting — cooking a meat or fish, packing it tight in a jar and sealing it under a layer of fat — was one of the standard English larder methods from the seventeenth century onward, applied to everything from beef and venison to char, lampreys and shrimps. The shrimp version is generally traced to the north-west coast, and Morecambe Bay brown shrimps in butter remain the best-known survival of the technique; the small sweet brown shrimp holds its texture under butter far better than a larger prawn. Cassell's, compiled for late-Victorian households that still kept a cold larder rather than refrigeration, treats the butter cap as a genuine preservative. The instruction to warm the shrimps with butter and seasoning before potting may have been meant to draw the spices into the flesh, though the recipe itself says only to bake until the butter is melted.