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Isinglass Jelly, Lemon
Peel the rind of two lemons, without any of the white inner skin, and put it into an ounce and a half of isinglass clarified in a pint of water, and sweetened according to taste--say with half a pound of loaf sugar. Strain the juice of four large lemons, and pour it gently into the isinglass when cool. Pour it at once (the lemon-rind must be taken out, but the liquid need not be strained) into small moulds, or into one large one, and cover with ice broken small. This jelly may be made from calf's foot stock. Put to each pint the juice of three lemons. Time, an hour to prepare. Probable cost, 2s. The above ingredients are sufficient for a pint and a half mould. ISINGLASS JELLY, LEMON (another way). (See LEMON ISINGLASS JELLY.)
A clear lemon jelly of the sort that anchored Victorian supper tables, built on isinglass rather than the sheet and powdered gelatines that replaced it. The method is sound; only the setting agent and the chilling need translation.
- The hinge: add the juice coldThe lemon juice goes in only when the isinglass liquid has cooled, as the recipe directs. Prolonged heating of a gelatinous liquid with strong acid can weaken the set, so the juice goes in off the heat.
- IsinglassPurified collagen from the swim bladders of sturgeon and related fish, sold in leaves or shreds and soaked, then simmered, to dissolve. It is now a brewing and conservation material rather than a kitchen one, and sturgeon products are trade-restricted; ordinary gelatine is the practical stand-in.
- Substituting gelatineDo not use 1½ oz of powdered gelatine. Isinglass of the period varied widely in strength and was used generously; modern gelatine is standardised and stronger by weight. Use the quantity the packet specifies for the finished volume -- the recipe says its ingredients suffice for a pint-and-a-half mould -- erring firm if you intend to turn it out.
- ClarifiedHere it most likely means the isinglass dissolved and strained clear of its own sediment and scum, rather than clarified with egg white, though period cooks did use whites and shells for jellies. Because the rind is lifted out and nothing cloudy is added, the finished jelly needs no further straining, as the text says.
- Loaf sugarRefined white sugar, sold as a hard cone to be nipped into lumps. Half a pound is a scant 1⅛ cups of granulated sugar, which is sweet but appropriate against four lemons' juice.
- Rind without pithPare the zest in wide strips with no white attached. The pith turns the jelly bitter and cloudy, and it steeps in the hot liquid long enough for that to show.
- Calf's foot stockThe stated alternative is a homemade gelatine from long-simmered calf's feet, strained and chilled so the fat can be lifted off. It generally sets softer and less clear than isinglass. The recipe allows three lemons to the pint for it, without saying why.
- Chilling"Cover with ice broken small" is the ice-house equivalent of refrigeration. Four hours in the refrigerator sets a small mould; a pint-and-a-half mould is safer left overnight. Unmould by dipping the outside briefly in warm water.
- YieldA pint-and-a-half mould serves six as a light dessert, or eight in small individual moulds.
Isinglass reached British kitchens through the northern European fish trade by routes that are not easily pinned down, and by the mid-nineteenth century it was the prestige setting agent: cleaner-tasting and far clearer than boiled calf's feet, and easier to keep to hand than a stock requiring a day's work at the stove. Clear jelly was a test of technique, judged on transparency and on whether it stood up when turned out. The alternative given here, calf's foot stock, is the older domestic method, and the recipe's careful note that it needs the juice of only three lemons to the pint reflects its weaker, softer set. Commercial powdered gelatine, cheap and consistent, eventually displaced both, and isinglass survives now mainly as a fining agent in beer and in the repair of parchment.