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Strawberry Jams
Boil mashed berries in their own juice till well reduced, when add heated sugar, three-fourths to each pint of fruit or pound for pound, cooking down slowly till of desired thickness. Strawberry jam is usually too sweet. To offset this do not be afraid to add lemon juice, pie plant, or other tart fruit. Also a very delicious variety may be had by using with the strawberries equal quantity of gooseberry, fig, date, pineapple, cherry, currant, red raspberry, or orange or lemon marmalade.
A jam formula rather than a fixed recipe: it gives you a ratio, a method, and a list of things to blend in. The two decisions that matter are how much sugar you commit to and how far you cook it down.
- The ratio, decoded"Three-fourths to each pint of fruit" appears to mean three-quarters of a pound of sugar (about 1 3/4 cups) for each pint of mashed berries; "pound for pound" is equal weights of fruit and sugar. Weigh the fruit rather than measuring the mash by volume — the weight of a pint of crushed strawberries varies with how hard you crush it, so the volume figure here is genuinely loose.
- Reduce first, then sweetenThis is the hinge. Cooking the mashed berries in their own juice before the sugar goes in drives off water while the fruit is still free to break down; sugar added early tends to firm the fruit by drawing water out of it, and the jam then needs longer boiling, which dulls the colour and flavour.
- Heated sugarWarming the sugar (a shallow pan in a 250F oven for ten minutes) keeps the boil from stalling when it hits the pot, so the mixture returns to temperature fast. Not essential on a modern burner, but it does shorten the cooking.
- Judging "desired thickness"Jam sets at 220F at sea level, about 8F above the boiling point of water where you are. Failing a thermometer, chill a saucer, drop a spoonful on it, and push it with a fingertip after a minute: it should wrinkle rather than run.
- Strawberries are low in pectin and low in acidThe advice to add lemon juice is not only about sweetness — the acid is what lets pectin gel. Two tablespoons of lemon juice per pound of fruit is a reasonable working amount. Gooseberry and currant bring both acid and pectin, and rhubarb brings acid, which is why they appear on the list.
- "Pie plant"Rhubarb. Use the stalks only, trimmed of all leaf; rhubarb leaves contain oxalic acid and are not eaten.
- Yield and keepingTwo pounds of berries with the lower sugar ratio gives roughly three to four half-pint jars, depending on how far you cook it down. There is no sealing instruction here, and the lower-sugar version in particular is not shelf-stable — refrigerate it and use it within about a month, or freeze it. For pantry storage, follow current water-bath canning directions for jam.
Jam recipes of this stamp — a ratio and a doctrine rather than a numbered procedure — were the norm in American household books before commercial pectin became widely available to home cooks, generally traced to around the end of the 1910s. Everything depended on the fruit's own pectin and acid, which is often said to be why writers of the period steered readers toward currants, gooseberries and rhubarb as correctives: they were the household's pectin supply. The complaint that strawberry jam "is usually too sweet" reflects the older pound-for-pound rule, inherited from preserving practice in which sugar was the preservative and the sweetness was the price of a jar that kept through winter. The list of blending fruits, running from gooseberry to fig, date and pineapple, shows a turn-of-the-century pantry that could draw on both the garden and the grocer's imported dried and canned goods.</p>