Why it works: Cider and vinegar are a kitchen classic. They rank in the top 6% of all ingredient pairs, and cooks put them together in 3,431 recipes. Both carry 4-ethyl-2-methoxyphenol, which smells smoky, clove. The science ↓
Pickled Onions
Ingredients
Directions
Prepare
Peel the onions without cutting off the tops.
Place them in a porcelain kettle with cold water and sweet milk.
Heat until hot but not boiling, then set aside for 15 minutes.
Spread the onions on a cloth-covered table to cool.
Pack and seal
Once cool, pack them into half-pint wide-necked glass jars.
Add a blade of mace and salt to each jar.
Fill the jars with cold cider vinegar, cork tightly, and seal with wax.
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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Cider + vinegartop 6% of all pairsSmell alikemoderateCooked together3,431 recipes
Shared aroma: 4-ethyl-2-methoxyphenol (smoky, clove).
-
Onion + vinegartop 14% of all pairsSmell alikemoderateCooked together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
-
Onion + macetop 17% of all pairsSmell alikelowCooked together7,078 recipes
Shared aroma: eugenol (clove, spicy).
-
Milk + macetop 17% of all pairsSmell alikelowCooked together3,346 recipes
Shared aroma: sabinene (woody, terpenic).
-
Mace + cidertop 18% of all pairsSmell alikelowCooked together658 recipes
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Button onions
- Provide the main body of the pickle, becoming tender and mild after the heating step.
- Sweet milk
- Its mild dairy proteins and sugars soften the sharp bite of the onions before pickling.
- Cider vinegar
- Acidity preserves the onions and gives the pickle its tangy, sharp flavour.
- Mace
- Adds a warm, aromatic spice note to the pickling liquid.
The step that matters
Heating without boiling. Heating the onions until hot but not boiling softens their sharp flavour and firms the texture. Boiling would make the onions soft and mushy, so the kettle should stay below a simmer.
Swap the mace
How well each one fits the dish's main ingredients (onion, milk, cider, vinegar):
- Garlicfits better
- Thymefits better
- Allspicefits better
- Macethe original
Fit is the average pairing score against onion, milk, 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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