Name: Tomato Catsup
Ingredients: 30 tomatoes; 4 onions; 4 peppers; 6 cups vinegar; 2 cups sugar; ½ cup coarse sea salt; 1 teaspoon cloves; 1 teaspoon cinnamon

Why it works: Clove and cinnamon match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 14,189 recipes. Both carry ethyl cinnamate, which smells sweet, balsamic. The science ↓

Tomato Catsup

Ingredients

Directions

Cook the base

Stew the tomatoes, onions, and peppers together until soft.
Strain the mixture to remove solids.

Season and finish

Add vinegar, sugar, salt, cloves, and cinnamon to the strained mixture.
Boil all ingredients together for a few minutes.
Bottle the catsup 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.

Clove + cinnamontop 1% of all pairs

Smell alikestrong

Cooked together14,189 recipes

Shared aroma: ethyl cinnamate (sweet, balsamic).
Pepper + clovetop 5% of all pairs

Smell alikestrong

Cooked together17,451 recipes

Shared aroma: ethyl octanoate (fruity, wine).
Tomato + peppertop 7% of all pairs

Smell alikemoderate

Cooked together17,923 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Tomato + oniontop 8% of all pairs

Smell alikemoderate

Cooked together20,633 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Pepper + cinnamontop 9% of all pairs

Smell alikestrong

Cooked together4,890 recipes

Shared aroma: methyl cinnamate (strawberry).

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

What each ingredient does

Tomatoes: Provide the main body, colour, and fruity base of the ketchup.
Vinegar: Adds sharp acidity that brightens flavour and helps preserve the sauce.
Sugar: Adds sweetness that balances the acidity of the vinegar and tomatoes.
Onions: Add savoury depth and aroma to the cooked base.
Peppers: Contribute vegetal flavour and aroma to the cooked base.

Swap the onion

How well each one fits the dish's main ingredients (tomato, pepper, vinegar, sugar, clove, cinnamon):

Capsicumfits better
Mustardfits better
Cucumberfits better
Onionthe original

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

“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.