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Plum and Lemon Jam
Use with greengages, the grated rind and juice of a lemon for each quart of fruit.
PLUM JELLY No. I If the plums are very tart or bitter a little soda may be added, about one dessertspoonful for each peck of fruit, letting all come to a boil. Drain and add fresh water, barely enough to cover, cooking down till plums are tender. Strain through a flannel bag (over night if possible; a cheese cloth bag will facilitate matters but it must not be squeezed). Let cook down one-fourth; skim and add sugar in equal proportion to weight of fruit. When sugar has dissolved the juice will jell in twenty minutes or under. PLUM JELLY No. 2 Use wild plums, the fruit or juice-one-third or one-fourth part plums-with juice of crab apples. This combination makes a beautiful colour and delicious flavour.
Three fragments run together here: a one-line variation on a preceding plum jam, then two jelly methods. The lemon note assumes the jam recipe printed above it, so treat it as an addition of grated rind and juice per quart of fruit to whatever plum jam base you are working from.
- The hinge: do not squeeze the bagPressing the pulp forces starch and fine solids through and turns the jelly cloudy. Hang the bag overnight and take only what drips, even though it feels wasteful.
- Skip the sodaBaking soda neutralises the very acid that plum pectin needs to set, and it froths violently when it hits hot fruit. Tart or bitter plums are an asset in jelly-making; a longer simmer and adequate sugar handle the flavour without chemistry.
- Old measuresA dessertspoonful is 2 teaspoons. A peck of plums is roughly 12-14 lb (a peck is a quarter bushel). A quart of fruit means a quart measured by volume in the whole state, near enough 1 1/2 lb of plums.
- "Cook down one-fourth"Most probably means reduce the strained juice by a quarter of its volume before the sugar goes in, though the phrase could also be read as reducing it to a quarter. Mark the level on a wooden spoon at the start so you can judge it.
- Sugar in equal proportionEqual weight of sugar to weight of fruit is the standard old ratio and it works, but weigh the strained juice rather than the original fruit for a jelly. A pound of sugar to a pound of juice is the usual reading.
- Testing the setTwenty minutes is a fair estimate but not a rule. Go by 220F on a thermometer at sea level, or by the cold-saucer test: a spoonful chilled a minute should wrinkle when pushed.
- Greengages and wild plumsGreengages are a green-skinned dessert plum, sweet and relatively low in acid, which is probably why the lemon is specified. Wild plums and crab apples are both high in pectin and acid, which is what helps jelly No. 2 set; commercial pectin should not be needed with them.
- StorageThe book says nothing about sealing. Current practice is to fill sterilised jars, seal, and process in a boiling water bath for 5-10 minutes; anything left unprocessed belongs in the refrigerator and should be used within a few weeks.
- YieldRoughly 4-5 half-pint jars from 4 lb of plums, depending on how much juice the fruit gives up.
Jelly of this kind belongs to the decades before packaged pectin, when a cook's skill lay in choosing fruit that would set itself. Wild plums and crab apples, both mentioned here, were American stand-bys precisely because they are sour and full of natural pectin, and the trick of blending a small proportion of one high-pectin fruit with a larger quantity of a weaker one is older than any commercial product. Greengages, at the other extreme, are sweet and low in acid, which is why the lemon appears; the variety is generally traced to the Gage family of Suffolk, who are said to have grown it in England in the eighteenth century, and it kept a reputation as the connoisseur's plum. Adding a little soda to blunt sourness or bitterness in fruit turns up in nineteenth-century household books, and the practice fell out of use as the role of acid in setting came to be better understood.