Coffee Jelly

A plain gelatine dessert that depends almost entirely on the quality of the coffee and the ratio of gelatine to liquid. Both need a moment's attention before you start.

• The gelatine is the hingeTwo tablespoons of granulated gelatine is roughly two and a half to three modern envelopes (a Knox-type envelope holds about 2 1/4 teaspoons, or 1/4 oz). Against 2 3/4 cups of total liquid that gives a firm jelly you can turn out of a mould and slice; for a softer, spoonable set, use one envelope per 2 cups of liquid.
• Soak, then dissolveThe fifteen-minute soak in cold water is blooming, and it is not optional with granulated gelatine — skip it and you get grains that never fully disperse. Once the boiling water and hot coffee go in, stir until you cannot feel any grit on the back of the spoon.
• "Boiled coffee"In this period that means coffee made in a pot on the stove, grounds and water together, and it is stronger and more bitter than drip. Use 1 3/4 cups of strong brewed coffee; because the sugar is fixed and the jelly is eaten cold, brew it a little stronger than you would drink, as chilling mutes both aroma and sweetness.
• Do not boil the mixtureAdd the hot liquids to the bloomed gelatine off the heat. Holding gelatine at a hard boil weakens its setting power, and there is no reason here to bring the pan back to the stove.
• "Set in a cold place"Written before home refrigeration was universal — a larder or icebox. In a modern refrigerator allow about 3 to 4 hours in a bowl or mould, less in individual glasses.
• ServingSix portions as written, a scant half-cup each. Cold coffee jelly is often served with cream, plain or lightly whipped, poured over rather than folded in.