Pineapple Jam

Two lines, no method beyond a boil time — this is a proportion rather than a procedure, which is how most fruit-and-sugar preserves were written before pectin came in a box. What it gives you is a soft, syrupy conserve, not a firm cut-and-spread jam.

• Loaf sugarLoaf sugar was refined white sugar broken from a cone or block, prized because it was cleaner than the grey unrefined sugar of the day. Ordinary granulated sugar is the direct replacement, weight for weight: ¾ lb is about 1⅔ cups.
• The ratio is low for a setModern jam recipes run close to equal weights of fruit and sugar, sometimes more. At 3 parts sugar to 4 parts fruit, and with pineapple carrying very little pectin, ten minutes will not give you a gel. Expect a loose, spoonable conserve — good on toast, better over ice cream or rice pudding.
• Grated pineappleFresh fruit, peeled, cored and taken down to a pulp on the coarse side of a box grater, juice and all. One pound of prepared pulp is roughly what a small pineapple yields. Well-drained canned crushed pineapple in juice works and behaves the same way in the pan.
• Boil hard, and stirTen minutes means ten minutes at a full rolling boil, not a simmer. Sugar this concentrated scorches easily once the free water goes, so use a wide heavy pan, stir across the bottom, and skim the foam before potting.
• Bromelain is not a problem hereRaw pineapple's enzyme will keep gelatine from setting, but boiling destroys it. If you later want to combine this jam with a gelatine dessert, the cooked jam is safe to use.
• YieldAbout one pint, or two half-pint jars, from a pound of fruit.
• StorageThe book assumes nothing about sealing. With this much fruit to sugar it is not a shelf-stable preserve — refrigerate and use within about three weeks, or freeze. For a jar you intend to keep in the cupboard, follow current boiling-water-bath directions and quantities.