Name: To Prepare Rennet
Ingredients: 1 calf's stomach; coarse sea salt; saltpetre; 1 teaspoon vinegar; 5 cups cold water; 2/3 cup rose brandy

Why it works: Rose and brandy work together. They rank in the top 15% of all ingredient pairs, and cooks put them together in 560 recipes. Both carry beta-damascenone, which smells apple, rose. The science ↓

To Prepare Rennet

Ingredients

Directions

Prepare the stomach

Remove the stomach from the calf immediately after it is killed and hang it in a dry, cool place for 4-5 days without washing it.
Turn the stomach inside out, remove all the curd by hand, and fill it with a mixture of saltpetre and coarse sea salt.
Place the filled stomach in a small stone pot. Add 1 teaspoon of vinegar. Sprinkle a handful of salt on top.
Cover the pot tightly and store it for use.

Make the rennet liquid

After 6-8 weeks, cut a piece of the rennet about 4-5 inches long.
Place the rennet in a large bottle that holds about 1.5 pints. Add 5 cups of cold water and 2/3 cup of rose brandy.
Seal the bottle tightly and shake before use.
1 tablespoon is sufficient for 1 quart of milk.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

Rose + brandytop 15% of all pairs

Smell alikemoderate

Cooked together560 recipes

Shared aroma: beta-damascenone (apple, rose).
Vinegar + brandytop 17% of all pairs

Smell alikemoderate

Cooked together344 recipes

Shared aroma: beta-damascenone (apple, rose).
Vinegar + rosetop 27% of all pairs

Smell alikelow

Cooked together96 recipes

Shared aroma: beta-damascenone (apple, rose).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Calf's stomach: Supplies the enzyme rennet that curdles milk.
Saltpetre: Preserves the stomach and inhibits spoilage during the long dry curing.
Coarse sea salt: Draws moisture out and helps preserve the stomach during curing.
Rose brandy: Acts as an alcohol base that helps preserve the rennet liquid.

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.