Why it works: Cucumber and onion match in chemistry and in kitchens. They rank in the top 8% of all ingredient pairs, and cooks put them together in 6,050 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 separately.
Add enough coarse sea salt to season and let them stand until water rises.
Squeeze the mixture dry.
Season and bottle
Mix the cucumbers and onions together, adding a little black pepper.
Add enough vinegar to cover the mixture.
Bottle and seal the catsup.
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 + oniontop 8% of all pairsSmell alikestrongCooked together6,050 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Cucumber + vinegartop 8% of all pairsSmell alikemoderateCooked together4,734 recipes
Shared aroma: 2-methylbutyl acetate (fruit).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Cucumber + peppertop 12% of all pairsSmell alikemoderateCooked together5,991 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + vinegartop 14% of all pairsSmell alikemoderateCooked together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Cucumbers
- Provide the main bulk and fresh flavour, and release water when salted.
- Onions
- Add pungency and savoury depth that balances the cucumber's mildness.
- Vinegar
- Adds acidity that sharpens flavour and helps preserve the mixture.
The step that matters
Squeezing the mixture dry. Salting draws water out of the cucumbers and onions. If that water is not squeezed out, the ketchup stays thin and watery and can dilute its flavour and keeping quality.
Swap the onion
How well each one fits the dish's main ingredients (cucumber, pepper, vinegar):
- Capsicumfits better
- Radishfits better
- Mustardfits better
- Onionthe original
Fit is the average pairing score against cucumber, pepper, 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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