Why it works: Celery and mustard are a kitchen classic. They rank in the top 2% of all ingredient pairs, and cooks put them together in 4,169 recipes. Both carry guaiacol, which smells smoky, sweet. The science ↓
Tomato Catsup
Ingredients
Directions
Make the ketchup
Slit the tomatoes and boil them in an earthenware or enamelled pan until the juice is extracted and the pulp is dissolved.
Strain the mixture first through a colander, then through a hair sieve.
Tie the black pepper, cloves, and celery seed in muslin and stir them into the strained mixture along with the mustard, coarse sea salt, and powdered mace.
Boil the mixture for five hours, stirring occasionally for the first four hours and continuously for the last hour.
Rest and bottle
Pour the catsup into a stoneware jar and leave it in the cellar on a stone floor for 12 to 14 hours.
Remove the celery seed, bottle the catsup, seal it, and store in a cool, dark place.
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.
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Celery + mustardtop 2% of all pairsSmell alikemoderateCooked together4,169 recipes
Shared aroma: guaiacol (smoky, sweet).
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Tomato + celerytop 4% of all pairsSmell alikemoderateCooked together3,377 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Pepper + clovetop 5% of all pairsSmell alikestrongCooked together17,451 recipes
Shared aroma: ethyl octanoate (fruity, wine).
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Pepper + celerytop 5% of all pairsSmell alikestrongCooked together16,012 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Clove + celerytop 6% of all pairsSmell alikestrongCooked together4,668 recipes
Shared aroma: gamma-decalactone (peach, creamy).
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, juice and pulp that form the ketchup base.
- Mustard
- Adds sharp, pungent flavour that balances the sweetness of the reduced tomato.
- Coarse sea salt
- Seasons the ketchup and draws out flavour while the mixture cooks down.
- Black pepper
- Adds mild heat and aromatic spice to the ketchup.
- Cloves
- Contribute warm, aromatic spice notes to the ketchup.
- Celery seed
- Adds a savoury, herbal aroma; it is removed before bottling.
The step that matters
Long, stirred boil. Tomatoes are thick and sugar-rich, so they scorch easily on the base of the pan. Stirring often during the first hours prevents sticking and burnt flavour, and continuous stirring in the final hour keeps the ketchup from catching as it thickens.
Swap the mace
How well each one fits the dish's main ingredients (tomato, pepper, clove, celery, mustard):
- Thymefits better
- Tarragonfits better
- Allspicefits better
- Macethe original
Fit is the average pairing score against tomato, pepper, clove, celery, mustard. 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.
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