Name: Tomato Catsup
Ingredients: 2 large onions; 4 green peppers; 2 tablespoons salt; 4 tablespoons brown sugar; 2 tablespoons ginger; 1 tablespoon cinnamon; 1 tablespoon mustard; 1 nutmeg (grated); 1 quart vinegar

Why it works: Cinnamon and nutmeg match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 11,917 recipes. Both carry estragole, which smells anise, licorice. The science ↓

Tomato Catsup

Ingredients

Directions

Peel the tomatoes and onions.
Chop the onions and peppers finely.
Boil all the ingredients together for 3 hours, or until soft and broken, stirring frequently.
Bottle and seal while hot.

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.

Cinnamon + nutmegtop 1% of all pairs

Smell alikestrong

Cooked together11,917 recipes

Shared aroma: estragole (anise, licorice).
Ginger + cinnamontop 1% of all pairs

Smell alikestrong

Cooked together6,380 recipes

Shared aroma: estragole (anise, licorice).
Ginger + nutmegtop 5% of all pairs

Smell alikestrong

Cooked together3,324 recipes

Shared aroma: estragole (anise, licorice).
Onion + mustardtop 6% of all pairs

Smell alikestrong

Cooked together9,259 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Cinnamon + mustardtop 7% of all pairs

Smell alikestrong

Cooked together1,581 recipes

Shared aroma: guaiacol (smoky, sweet).

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

Swap the onion

How well each one fits the dish's main ingredients (pepper, sugar, ginger, cinnamon, mustard, nutmeg, vinegar):

Horseradishfits better
Capsicumfits better
Shallotfits better
Onionthe original

Fit is the average pairing score against pepper, sugar, ginger, cinnamon, mustard, nutmeg, vinegar. Candidates are from the same food group and used in at least 100 recipes.