Why it works: Cucumber and mustard match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 2,281 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Cucuhber Catsup
Ingredients
Directions
Prepare
Peel and grate the cucumbers.
Add the chopped onions and coarse sea salt.
Drain the mixture overnight.
Season and cover
Mix in the mustard seed and black pepper.
Cover the mixture with cider vinegar.
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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Cucumber + mustardtop 3% of all pairsSmell alikestrongCooked together2,281 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + mustardtop 6% of all pairsSmell alikestrongCooked together9,259 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Cider + vinegartop 6% of all pairsSmell alikemoderateCooked together3,431 recipes
Shared aroma: 4-ethyl-2-methoxyphenol (smoky, clove).
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Mustard + vinegartop 7% of all pairsSmell alikemoderateCooked together14,067 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Cucumber + oniontop 8% of all pairsSmell alikestrongCooked together6,050 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Cucumbers
- Provide the bulk and fresh, watery body of the ketchup.
- Coarse sea salt
- Draws water out of the cucumbers and onions and seasons the mixture.
- Onions
- Add savoury depth and a sharp aroma.
- Mustard seed
- Adds a pungent, sharp flavour that carries through the ketchup.
- Cider vinegar
- Adds acidity that gives the ketchup its tang and helps keep it preserved.
The step that matters
Drain the mixture overnight. Salt pulls water out of the grated cucumber and onion through osmosis. Draining long enough removes that liquid so the ketchup stays thick rather than thin and watery.
Swap the onion
How well each one fits the dish's main ingredients (cucumber, mustard, pepper, cider, vinegar):
- Horseradishfits better
- Radishfits better
- Lettucefits better
- Onionthe original
Fit is the average pairing score against cucumber, mustard, pepper, cider, vinegar. 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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