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Red Raspberry Jam
Six pounds berries, four pounds sugar; boil berries twenty minutes, then add sugar and boil until thick.
A two-line jam recipe of the old open-kettle school, which assumes the cook knows what "thick" looks like. The proportions are sound; the timing is where it needs interpretation.
- The hinge: judge by set, not by clock"Boil until thick" means boil until the syrup sheets off a spoon or a candy thermometer reads 220F at sea level (subtract about 2F per 1,000 feet of elevation). A cold-plate test — a spoonful chilled a minute, then nudged with a fingertip to see if it wrinkles — is the traditional check and still the most reliable one.
- The twenty-minute pre-boilBoiling the fruit alone for twenty minutes was meant to break it down and drive off water before the sugar went in. It also destroys a good deal of raspberry pectin and most of the fresh flavour. Ten minutes of gentle cooking to release the juice is plenty; the sugar stage will do the rest of the thickening.
- Quantities in modern termsSix pounds of raspberries is roughly 22 cups, or about eight of the 12-oz supermarket clamshells. Four pounds of sugar is about 9 cups. The ratio is two parts fruit to a little over one part sugar by weight — leaner than the equal-weight jams common in period cookbooks, so expect a soft, loose set rather than a firm one.
- Use a wide, heavy panEvaporation is what thickens this jam, so surface area matters more than depth. A wide preserving pan or Dutch oven filled no more than a third full keeps the boil from climbing over the sides once the sugar goes in.
- Skim and stirSugared fruit scorches easily. Stir across the bottom regularly with a flat wooden spoon or heatproof spatula, and skim the pink foam that rises or the finished jam will look cloudy.
- SeedsNothing here strains the fruit, so this is a seedy jam by design. If you want it smooth, press half the cooked fruit through a fine sieve before adding sugar and accept a smaller yield.
- Yield and keepingExpect roughly a dozen half-pint jars. The recipe gives no instruction for sealing them, and the sealing-wax and inverted-jar methods of the period are not adequate today: refrigerate or freeze what you make, or follow a current tested water-bath canning process if you want shelf-stable jars.
Raspberries are among the easier fruits to preserve without help: they carry useful acid and a moderate amount of pectin, which is part of why nineteenth-century recipes for them are so bare, with no lemon, no added pectin and no thermometer. Commercial pectin — Certo, in liquid form — reached American home kitchens in the 1910s, so the cook using this book had to read the set by eye, and short recipes like this one assume she could. As refined sugar grew cheaper through the later 1800s, household jams tended to grow sweeter, though a single fruit-to-sugar ratio is not on its own enough to date a recipe.