Why it works: Mustard and vinegar are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 14,067 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓
Egg Sauce
Ingredients
Directions
Make the sauce
Mash the yolks of the hard-boiled eggs in a bowl.
Add mustard, pepper, salt, vinegar, and salad oil to the mashed yolks and mix until smooth and well combined.
Stir in ketchup if desired.
Serve
Serve the sauce with boiled fish.
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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Mustard + vinegartop 7% of all pairsSmell alikemoderateCooked together14,067 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Mustard + peppertop 9% of all pairsSmell alikemoderateCooked together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Pepper + vinegartop 14% of all pairsSmell alikemoderateCooked together27,814 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Mustard + ketchuptop 17% of all pairsSmell alikemoderateCooked together331 recipes
Shared aroma: ethanol (alcoholic, ethereal).
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Vinegar + ketchuptop 21% of all pairsSmell alikelowCooked together737 recipes
Shared aroma: ethanol (alcoholic, ethereal).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Egg yolks
- Emulsify with the oil and form the body of the sauce, giving it richness and a smooth texture.
- Mustard
- Adds sharp flavor and helps stabilize the emulsion of yolk and oil.
- Vinegar
- Adds acidity that brightens the rich yolk and oil.
- Salad oil
- Supplies fat that, emulsified with the yolks, gives the sauce its creamy body.
The step that matters
Mix until smooth and well combined. Mashed yolks and oil only form a stable emulsion when they are thoroughly blended, so incomplete mixing can leave the sauce greasy or separated.
Flavor stand-ins for the mustard
How well each one fits the dish's main ingredients (egg, pepper, vinegar, ketchup):
- Capsicumbetter flavor fit
- Horseradishabout as good a flavor fit
- Mustardthe original
- Shallotabout as good a flavor fit
Fit is the average pairing score against egg, pepper, vinegar, ketchup. Candidates are from the same food group and used in at least 100 recipes. This compares flavor only: it does not check the job the ingredient does in the dish (bulk, moisture, acidity, structure).
“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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