Why it works: Onion and vinegar are a kitchen classic. They rank in the top 14% of all ingredient pairs, and cooks put them together in 18,226 recipes. Both carry acetic acid, which smells sour, vinegar. The science ↓
Pickled Onions
Ingredients
Directions
Prepare the onions
Peel the small white onions.
Boil the onions in equal parts of sweet milk and water for 10 minutes.
Pickle and seal
Drain the onions and pour boiling spiced vinegar over them.
Seal the container.
Tie the spices in a cloth to prevent them from darkening the onions.
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.
-
Onion + vinegartop 14% of all pairsSmell alikemoderateCooked together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
-
Onion + milktop 20% of all pairsSmell alikemoderateCooked together13,418 recipes
Shared aroma: hexanal (green, grassy).
-
Milk + vinegartop 28% of all pairsSmell alikemoderateCooked together2,949 recipes
Shared aroma: isoamyl acetate (banana, pear).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Small white onions
- The main vegetable, which takes on the vinegar and spice flavours as it pickles.
- Sweet milk
- Boiling in milk mellows the sharp flavour of the onions.
- Boiling spiced vinegar
- Acidity that sharpens the flavour and helps preserve the onions.
- Spices
- Provide aroma and flavour; the cloth keeps them from staining the onions.
The step that matters
Drain the onions and pour boiling spiced vinegar over them.. Draining well keeps leftover boiling water from diluting the vinegar. Boiling-hot vinegar penetrates the onions more readily and keeps the brine strong enough to pickle them.
Swap the onion
How well each one fits the dish's main ingredients (milk, vinegar):
- Capsicumfits better
- Potatofits better
- Mustardfits better
- Onionthe original
Fit is the average pairing score against milk, 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.
More pickled onions recipes
You might also like
Tomato Soup526 recipes
Brown Bread461 recipes
Mutton Broth292 recipes
Yorkshire Pudding264 recipesThe free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.