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RENNET (other ways)
For the preparation of rennet there are many recipes; the following will be found one of the best. Take a calf's stomach-bag or maw, wash it clean, salt it thoroughly inside and out, and let it lie for two or three days. Hang it up to drain for another two or three days, then re-salt it, and put it into a jar covered with paper, pricked with pinholes. It may be used in a few days, but keeping improves it. When prepared for use, a handful of sweetbrier leaves, of dog-rose leaves, and of bramble leaves, together with three or four handfuls of salt, are boiled in a gallon of water for a quarter of an hour, and when quite cold the salted maw is added, together with a lemon stuck round with a quarter of an ounce of cloves. There must be enough salt to admit of some remaining always at the bottom undisturbed, and the liquor must be skimmed as often as is necessary.
This is a set of instructions for curing a raw calf's stomach into a coagulant for cheese-making. It is an uncontrolled cure of raw offal held at room temperature, and the points below explain why it cannot be followed today.
- Raw offal, never cookedThe maw is never heated at any stage: the leaf-and-salt liquor is boiled, then cooled completely before the stomach goes in. (Heat would in any case destroy the coagulating enzyme, though the recipe gives no reason.) The finished liquid is a raw animal extract added cold to milk.
- No measured salt concentration"Salt it thoroughly" and "three or four handfuls" give no brine strength. Safe salt curing depends on a known concentration of salt in water; below it, the same warm, moist, protein-rich conditions that preserve the maw instead favour Clostridium and other spoilage organisms. The instruction to keep undissolved salt on the bottom is an attempt at saturation by eye, not a control.
- No temperature, no time limitTwo or three days salting, two or three days draining, then indefinite storage in a paper-covered jar, all at whatever the larder happened to be. Nothing in the method establishes that the interior of a thick muscular stomach ever reaches a preserving salt level before it spoils.
- Skimming is not a safeguard"The liquor must be skimmed as often as is necessary" acknowledges that the jar throws up scum. Removing visible growth from the surface does not remove what has already diffused through the brine or the tissue.
- Unmeasured, unknowable strengthEven setting hygiene aside, this rennet has no rated activity, and the recipe gives no guidance on how much to use. Modern cheese recipes are written for standardised rennet with a stated dosage; a homemade extract cannot be substituted with any predictability.
- The foraged leavesSweetbrier, dog-rose and bramble leaves are astringent and were believed to help preserve and flavour the liquor. They contribute no coagulating power, and wild-gathered foliage is an additional and unnecessary microbial variable here.
- What to use insteadStandardised animal rennet, microbial rennet and fermentation-produced chymosin are all sold in small quantities for home cheese-making, with dosage on the label. Follow a current cheese recipe and its rennet instructions.
- Reading the originalThe "maw" is the fourth stomach chamber of an unweaned calf, the abomasum. The gallon is an imperial gallon, about 4.5 litres, and the quarter-ounce of cloves about 7 g — noted for sense of scale only.
Rennet is the oldest coagulant in cheese-making: the abomasum of a milk-fed calf secretes chymosin, which clots milk without souring it, and most hard cheese traditions in Europe rest on it, though plant coagulants were used in Iberia and elsewhere. Before the trade in standardised extracts, a dairy farm or large household prepared its own maws, which is why a general cookery dictionary like Cassell's carries the method at all. The salt-and-wild-leaf infusion is a preserving liquor of a type found across British and northern European dairying, and the lemon stuck with cloves is the same aromatic device used in brines and mulled drinks of the period. Commercial standardised liquid rennet came onto the market in the later nineteenth century and steadily displaced home preparation; by the time this edition was in kitchens, the recipe was already a survival from an older dairy economy.