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RASPBERRY AND RHUBARB JAM (an excellent family preserve)
Choose sound, newly-gathered raspberries and well-grown juicy rhubarb, and weigh them after the rhubarb has been pared and the raspberries have been stripped from the stalks. Take double the weight of raspberries to that of rhubarb, and allow three pounds of powdered loaf sugar to every four pounds of fruit. Slice the rhubarb, put it into a preserving-pan, and let it simmer gently for a quarter of an hour from the time it begins to boil, stirring it occasionally to keep it from burning to the bottom of the pan. Add the raspberries, and boil them half an hour. Stir in the sugar, and boil the jam until it will set when a little is put upon a plate. Pour it immediately into jars, and cover these in the usual way. Keep the jam in a dry airy place. Probable cost, 7d. per pound.
A straightforward two-fruit jam, but the sugar ratio and the vague sealing instruction both need attention before you start.
- Rhubarb leavesUse the stalks only. The leaves contain high levels of oxalic acid and are not edible; "pared" here means trimming the stringy outer skin from coarse, well-grown stalks, which is unnecessary with modern thin-stemmed rhubarb.
- Powdered loaf sugarLoaf sugar was refined sugar sold in a cone and crushed at home; powdered loaf sugar is simply fine granulated sugar, not modern icing/confectioners' sugar, which contains cornstarch. Ordinary caster or granulated sugar is the equivalent.
- The proportionsTwice as much raspberry as rhubarb by prepared weight, then 3 lb sugar to every 4 lb fruit. A practical batch: 2 lb raspberries, 1 lb sliced rhubarb, 2 lb 4 oz sugar.
- Sugar is low by modern standardsThat works out to roughly 43 percent sugar by weight of the raw mixture, against the near-equal weights of fruit and sugar in most modern jam recipes. Boiling to setting point concentrates it further, but the lower proportion leaves less margin, so expect a softer set and shorter keeping. Either process the filled jars in a boiling-water bath, or treat it as a refrigerator jam and use it within a few weeks.
- "Cover in the usual way"In this period that generally meant a disc of brandy-soaked paper with a paper or bladder cover tied down over the mouth of the jar; seals of melted fat or wax are also recorded. Neither is recommended now; use clean hot jars with two-piece lids and a water-bath process, or freeze.
- The boiling times are excessiveFifteen minutes for the rhubarb and a further half hour for the raspberries before any sugar goes in will reduce the fruit to a purée and drive off much of the pectin's setting power. Cooking the rhubarb until collapsed (10 minutes), then the raspberries just until broken down (5-10 minutes), gives a fresher jam.
- The setting testThis is the hinge of the recipe and it is the only reliable guide. Chill a saucer, drop on a little jam, wait a minute, and push it with a fingertip: it should wrinkle. On a thermometer this corresponds to about 220F/105C at sea level.
- Pan and yieldA "preserving-pan" is a wide, heavy pan, traditionally unlined copper or brass; any wide stainless or enamelled pot works, and width matters more than depth for evaporation. The batch above yields roughly six half-pint jars, depending on how far it is boiled down.
Cassell's treats rhubarb as the thrifty preserver's friend: it comes early, it grows in every back garden, it is acidic, and it stretches a smaller quantity of costlier soft fruit. Raspberries were expensive and short-lived, so pairing them two to one with rhubarb produced something that tasted mainly of raspberry at a price the book could quote as 7d. per pound — the "probable cost" is given for most entries in the volume, a reminder that its readers were budgeting household expenditure to the penny. Rhubarb had only relatively recently become a common English food plant; it was grown for medicine long before it was eaten, and the Yorkshire forcing trade that made cheap winter rhubarb possible was growing through roughly this period. The instruction to keep the finished jam "in a dry airy place" belongs to an era before reliable seals, when jam spoiled from mould on the surface rather than from anything sealed inside.