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Blackberry Jelly
Blackberries 1/2 pound sugar to every pint of juice Put as many blackberries as desired into a jar, and sprinkle a little sugar over; then put in the oven for three hours to draw out the juice. When sufficiently tender, strain through coarse muslin or cloth, squeezing out as much juice as possible. To each pint of juice allow half a pound of lump sugar, and boil in a preserving pan until it is set.
A very old-fashioned two-stage jelly: the juice is drawn out with gentle oven heat rather than boiled with water, which gives a clearer, more strongly flavoured result. The recipe assumes you know when jelly is set, so that is the part worth pinning down.
- The hinge: setting pointBoil the sweetened juice to 220F/104C, or test on a chilled saucer — a spoonful should wrinkle when pushed with a fingertip. Blackberries are only moderately high in pectin, and overripe fruit has less still, so include some red, barely ripe berries or add the juice of a lemon per pint to help the set.
- Oven for drawing juice"Put in the oven for three hours" implies gentle heat rather than a hot oven; the book names no temperature, but something around 250-275F/120-135C, with the jar covered, suits the purpose -- collapsing the fruit and releasing juice without evaporating it or scorching the sugar at the bottom of the jar.
- The jarUse a deep ovenproof bowl or a stoneware crock with a lid or a plate over it, standing in a roasting tin of water if your oven runs hot. A modern glass canning jar is not ideal for dry oven heat.
- Lump sugarLoaf or lump sugar was prized for purity, since unrefined sugar clouded jelly and threw more scum. Ordinary granulated white sugar is the direct equivalent; half a pound is a generous cup.
- StrainingCoarse muslin means an unbleached cloth or a jelly bag. Squeezing gives more juice but a cloudier jelly — if clarity matters, let it drip undisturbed for several hours instead.
- Preserving panA wide, heavy, shallow pan of stainless steel or copper. Depth works against you: the wider the surface, the faster the water goes off and the less the fruit flavour cooks away. Avoid bare aluminium or iron with acidic fruit.
- YieldYields vary with the fruit and how hard it is pressed: something in the region of 4 lb of blackberries may give around a quart of juice, enough for perhaps four half-pint jars. Skim the foam before potting.
- Keeping itThe book gives no instruction for sealing. Poured hot into sterilised jars and sealed, it keeps in the refrigerator for a month or two; for shelf storage, follow current guidance on a boiling-water bath.
Drawing fruit juice out in the oven was a familiar method in nineteenth-century British kitchens, when a coal range held residual heat for hours after the day's cooking and a covered crock could be tucked into the cooling oven at no extra cost. Blackberries were gathered from hedgerows in late summer and early autumn rather than bought, which is one reason they appear so often in household books aimed at economy. This one comes from a meatless cookery collection, part of the vegetarian and food-reform publishing of the period. The instruction to allow half a pound of sugar to a pint of juice, rather than to weigh the fruit, is a long-standing jelly-maker's rule and still a sound one.