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 ↓
Cucumber Catsup
Ingredients
Directions
Prepare
Peel and finely chop the cucumbers and onions.
Sprinkle the chopped vegetables with coarse sea salt and place in a sieve.
Let the mixture drain overnight.
Make the catsup
Add mustard seed and ground black pepper, and mix well.
Cover the mixture with cider vinegar and seal tightly.
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
- Form the bulk of the catsup and supply its fresh, crisp texture.
- Onions
- Add savory flavor and body to the chopped vegetable mixture.
- Coarse sea salt
- Draws water out of the chopped vegetables during draining, concentrating their flavor.
- Mustard seed
- Adds pungent, sharp flavor that develops as the catsup matures.
- Ground black pepper
- Contributes sharp, warm spice that balances the vegetables.
- Cider vinegar
- Adds acidity that preserves the mixture and gives it tang.
The step that matters
Draining overnight with salt. Salt draws water out of the chopped cucumbers and onions. Draining long enough removes that liquid, so the catsup stays thick rather than watery and keeps its texture once sealed with vinegar.
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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