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Strawberry Jam
1 heaping bowl strawberries 1 bowl (scant) sugar.
Set on hot stove and stir to dissolve the sugar. Let boil hard for 10 minutes.
Skim and bottle.
Four lines of instruction, and almost everything hangs on the boil. This is a small-batch, high-sugar jam made by volume rather than weight, in the days when a cook judged setting by eye.
- What a "bowl" meansNo size is given, so the measure reads as a ratio rather than a quantity, most likely the same bowl filled twice: roughly equal volumes of fruit and sugar, with the fruit heaped and the sugar levelled off short. If you take the bowl as a quart, that lands near 4 cups hulled berries (about 1 1/2 lb) to a slightly scant 4 cups sugar (about 1 3/4 lb).
- The ten minutes is not a ruleTen minutes of hard boiling is a starting estimate for a small pan, not a set point. Strawberries are low in pectin, so judge by temperature — 220F at sea level — or by the wrinkle test on a chilled saucer. A wide, heavy pan boils down faster than a deep one and gives brighter fruit.
- No pectin, no lemonWith neither added, the set depends on sugar concentration alone, which means a soft, spoonable jam rather than a firm one. A tablespoon of lemon juice sharpens the flavour and helps the natural pectin along; slightly underripe berries help more than ripe ones.
- Stir before it boils, not afterThe instruction to "stir to dissolve the sugar" matters: undissolved sugar on the pan bottom scorches and can crystallise in the jar. Once the syrup is clear and boiling, stir only enough to keep it from catching.
- SkimmingThe foam is trapped air and protein, harmless but cloudy. Skim at the end rather than throughout, or drop in a small knob of butter, which collapses most of it.
- "Bottle" is open-kettle sealingPouring boiling jam into jars and capping them was standard then and is no longer considered a reliable seal. Fill clean hot half-pint jars, leaving 1/4 inch of headspace, and process 10 minutes in a boiling water bath; or skip that and keep the jam in the refrigerator, where it lasts a month or two.
- YieldAbout three to four half-pint jars. The recipe scales badly upward — doubling it lengthens the boil, dulls the colour and pushes the flavour toward cooked-fruit; make two batches instead.
The Five Roses Cook Book was published by the Lake of the Woods Milling Company of Montreal, one of a large family of flour-company cookbooks distributed to Canadian households in the early twentieth century, and its brevity is characteristic: these books were compiled from contributed recipes by women who already knew how to cook and needed only a reminder of proportions. The bowl-for-bowl measure is older than the book and older than reliable kitchen scales, the sugar acting as the preservative rather than a flavouring. The short, hard boil is a comparatively modern method: earlier jams were often simmered far longer, which darkened them, and the move to a fast boil reflected a growing preference for fresh fruit colour and flavour, later made routine by commercial bottled pectin.