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 the cucumbers and slice them thinly.
Cover the slices with ½ pint of coarse sea salt to draw out the water.
Chop the onions finely and add to the cucumbers.
Season and rest
Mix in the mace, Madeira wine, sweet oil, cayenne pepper, and black pepper.
Let the mixture sit for a few hours before using.
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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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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Mace + peppertop 16% of all pairsSmell alikelowCooked together12,257 recipes
Shared aroma: myristicin (spice, warm).
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Onion + macetop 17% of all pairsSmell alikelowCooked together7,078 recipes
Shared aroma: eugenol (clove, spicy).
Mace and pepper barely smell alike, yet cooks put them together in 12,257 recipes: they work on texture and structure more than aroma.
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Cucumbers
- Provide the bulk of the ketchup; salting draws out their water so the sauce thickens.
- Coarse sea salt
- Draws water out of the cucumber slices, concentrating flavor and firming the texture.
- Onions
- Add pungent sharpness and savory depth that balances the sweetness of the wine.
- Madeira wine
- Adds sweetness and rich, caramel-like aroma to the sauce.
- Sweet oil
- Adds fat that carries the spices and gives a smoother mouthfeel.
The step that matters
Salting the cucumber slices. Salt pulls water out of the cucumbers by osmosis. Enough salt and time are needed to draw out the liquid, otherwise the ketchup stays thin and watery.
Swap the mace
How well each one fits the dish's main ingredients (cucumber, onion, madeira wine, pepper):
- Garlicfits better
- Thymefits better
- Parsleyfits better
- Macethe original
Fit is the average pairing score against cucumber, onion, madeira wine, pepper. 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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