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Jelly, Isinglass Clarified For
Put an ounce of isinglass into an enamelled saucepan with half a pint of water. Bring it slowly to a boil, then draw the pan to the side of the fire, and simmer gently for half an hour, being careful to stir the isinglass constantly, to prevent it sticking. Remove the scum as it rises, and put it on a sieve which has been moistened with boiling water. A little clear jelly may drain from it, and this may be added to the isinglass. A tea-spoonful of cold water should be put in two or three times to assist the scum in rising. When the jelly is required exceedingly transparent, a tea-spoonful of beaten white of egg may be added to the water in which the isinglass is dissolved, but when this is done, a little more isinglass should be allowed, as the white of egg has a tendency to weaken it. An ounce of isinglass is usually considered necessary for a pint of juice. Probable cost, 1s. 2d. per ounce. Sufficient, half a pint of water for an ounce of isinglass.
This is a base preparation rather than a finished dish: a clear setting agent to be stirred into fruit juice, wine or cream. Almost nothing here translates directly, since the main ingredient has effectively left the domestic kitchen.
- What isinglass isDried collagen from the swim bladders of fish, sold in shreds, leaves or ribbons. It still exists as a brewing fining and for conservation work, but the kitchen grade the book assumes is no longer stocked by grocers; leaf or powdered gelatine has taken its place entirely.
- The hinge: never let it boil hardBring it slowly to the boil, then move it off the direct heat. A rolling boil drives off water, scorches the collagen against the pan bottom and clouds the result, which defeats the whole purpose of the operation.
- MeasuresHalf a pint is 10 fl oz in British Imperial measure, so about 1¼ US cups; an ounce is 28 g. The working ratio the book gives is 1 oz isinglass to 1 pint (20 fl oz) of juice.
- Strength is not comparable to gelatineThat ratio would be very stiff by modern standards, where roughly 7 g of powdered gelatine is usually reckoned to give a soft set to a pint. Isinglass as sold was variable in quality and partly insoluble, and Victorian moulded jellies were built to stand up unsupported on a dish. Do not read across the quantities.
- "Draw the pan to the side of the fire"A range instruction, meaning the coolest part of the hob. On gas or induction it is the lowest setting that keeps a lazy tremor at the surface for the full half hour.
- Why enamelledCast iron and unlined copper both discolour and taint pale jellies. Any non-reactive pan does the job: stainless steel, enamel, or a lined pan.
- The cold-water trickA spoonful of cold water dropped in briefly stops the simmer and lets suspended scum rise to be lifted off. It is the same principle as topping a stock pot, and it works.
- The egg-white clarificationBeaten white coagulates as it heats and carries fine particles up into the scum. The book is right that it also costs you setting power, hence the instruction to allow a little extra isinglass.
- The moistened sieveWetting the sieve or cloth with boiling water stops the jelly chilling and gelling in the mesh. Strain while everything is hot and work quickly.
- Cost1s 2d an ounce was not trivial in a late-Victorian household budget, which is why the entry frets over waste and over the jelly that drains from the scum.
Isinglass came into English kitchens through the Russian trade, the best grades being made from sturgeon swim bladders and often sold under names like leaf, book, purse or staple isinglass; cheaper sorts were later worked up from cod, hake and other fish. Alongside its use in puddings it was, and remains, a fining agent for beer and wine, which is why brewers' catalogues outlasted the culinary supply. A clear, reliable jelly stock underpinned a whole class of Victorian table pieces: moulded fruit jellies, charlottes, creams and blancmanges, all turned out of shaped tins and expected to hold their edges. The obsessive skimming and the egg-white raft belong to the same aesthetic that prized glassy transparency in a jelly as proof of a careful kitchen. Refined commercial gelatine, cheaper and standardised in strength, displaced isinglass in domestic cookery over the following decades.</p>