Coffee Jelly
One box Cox's gelatine, put to soak in one pint cold water, for about an hour; then add three pints rather scant of strong boiling coffee, and sweeten to taste; wet tea-cups with cold water and half fill them with the jelly; when thoroughly cold turn them out and eat with sweetened cream, or whipped cream, sweetened and flavored slightly with vanilla.
A four-pint batch of coffee jelly turned out of teacups. The only real difficulty is the gelatine: the strength of a nineteenth-century "box" is not something you can assume.
- Cox's gelatine boxCox's Sparkling Gelatine, made in Edinburgh, was sold in a packet generally reckoned at about an ounce, or roughly four modern quarter-ounce envelopes. An ounce will barely hold four pints of liquid, and certainly not firmly enough to unmould, so treat the original quantity as unreliable rather than authoritative.
- How much to use insteadFor jelly stiff enough to turn out of a cup, count on one envelope of powdered gelatine (about 2¼ teaspoons) per 1½ cups of liquid — five to six envelopes for the eight cups here. Softer spooned-from-the-glass jelly needs about half that.
- Soaking still mattersThe hour in cold water is blooming, and it is not optional with sheet or older granulated gelatine; powdered gelatine needs only five to ten minutes. Sprinkle it over the surface of the cold water rather than dumping it in a heap, or the centre stays gritty.
- Boiling coffeeThe boiling coffee is what dissolves the bloomed gelatine, and that is fine — but stir off the heat and do not return the mixture to a boil or hold it hot for long, which slowly weakens the set.
- "Strong coffee"Sweetening and cream both mute coffee flavour, so brew noticeably stronger than you would drink: roughly one and a half times your normal ratio. Sweeten while the mixture is hot, when sugar dissolves without stirring in air.
- Chilling and unmouldingWetting the cups is right — a film of water breaks the suction and lets the jelly slide. Allow at least six hours in the refrigerator, or overnight; the recipe's "thoroughly cold" gives no time at all, and an unheated larder would have been slower than a modern refrigerator.
- YieldEight cups of liquid, half-filling teacups, gives roughly sixteen to twenty servings. The recipe halves without adjustment.
Coffee jelly belongs to the long Victorian enthusiasm for moulded gelatine, which shifted from a laborious kitchen project — calves' feet boiled for hours and the stock clarified with egg white — to a boxed convenience in the second half of the nineteenth century. Cox's of Edinburgh and, in America, Charles Knox and later Jell-O made a set dessert something a household could produce on a weekday, and coffee, chocolate and wine jellies followed quickly. A cold jelly with cream suited a light evening meal: it could be made in the morning and left to set, requiring nothing of the cook at the hour it was served. The dish never entirely disappeared — it remains a fixture in Japan, where kōhī zerī arrived with Western-style café culture and is still sold in cups with a jug of cream.