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Rennet, Liquid
Take twelve ounces of fresh rennet, cut small, and three ounces of common salt; knead them together, and leave the mixture at rest in a cool place for five or six weeks; then add eighteen ounces of water and two ounces of good proof spirit or rum. Digest for twenty-four hours; filter the liquid, and colour it with a little burnt sugar. Two or three tea-spoonfuls will curdle a quart of milk.
This is a preparation for an ingredient rather than a dish: an extract of calf stomach used to set junket and soft cheese. It cannot be recommended today, and the notes below explain the specifics.
- What "fresh rennet" meansThe rennet here is the raw lining of the fourth stomach (the abomasum) of an unweaned calf, known in some regions as vell. The recipe specifies it fresh; almost no modern retail butcher can supply it.
- Why the curing step fails modern standardsTwelve ounces of raw stomach tissue is held in a "cool place" for five or six weeks with no stated temperature. A Victorian larder might sit anywhere from 40F to 60F depending on the season, and three ounces of salt worked into moist tissue gives no reliable guarantee of inhibition across that range. The instruction has no measurable control point at all.
- The extract is never heatedThe finished liquid is filtered cold, kept cold, and stirred into milk that is also never cooked — junket is set at blood heat and eaten as it is. Anything surviving the cure passes straight into the finished dish. Commercial rennet is produced under controlled conditions and filtered to a defined standard precisely because of this.
- Strength cannot be judged"Two or three tea-spoonfuls will curdle a quart of milk" assumes an enzyme activity that varies enormously with the age of the calf, the freshness of the stomach and the length of the cure. Modern rennet is sold with a stated coagulating strength for exactly this reason; a home extract gives you no way to know whether you have a weak set or an over-firm, bitter one.
- The spirit is not a preservative hereTwo ounces of proof spirit in eighteen ounces of water works out to somewhere in the region of five per cent alcohol in the finished liquid — enough to slow spoilage of the strained extract a little, nowhere near enough to sterilise it or to justify the weeks of unrefrigerated curing that came before.
- Burnt sugarCaramel colouring, made by cooking sugar dark. It is purely cosmetic.
- If you want to set milkBuy rennet — animal, microbial or fermentation-produced chymosin — from a cheesemaking supplier and follow the dosage on the bottle. A few drops set several litres, and the strength is stated.
Rennet has been the standard milk-coagulant of European cheesemaking for as long as cheese has been recorded, and the domestic English use was narrower still: setting junket, a sweetened curd flavoured with brandy or nutmeg and dusted with cinnamon, which was a nursery and invalid dish throughout the nineteenth century. A dried salted vell from the butcher could be steeped in water as needed, or a keeping liquid made of the kind described here. Bottled rennet extract became a commercial product from the 1870s onward. The word itself is generally traced to the same Old English root as run — the sense being milk that runs together, or curdles.