Name: Onion Pickles
Ingredients: 1 quart vinegar; 2 teaspoons whole black pepper; 2 teaspoons allspice; Onions

Why it works: Pepper and allspice match in chemistry and in kitchens. They rank in the top 5% of all ingredient pairs, and cooks put them together in 6,395 recipes. Both carry estragole, which smells anise, licorice. The science ↓

Onion Pickles

Ingredients

1 quart vinegar
2 teaspoons whole black pepper
2 teaspoons allspice
Onions

Directions

Gather dry, ripe onions and remove the thin outer skin with your fingers.
Use a silver knife to remove one more skin until the onion looks clear.
Place the peeled onions in very dry bottles or glass jars.
Pour cold vinegar over the onions to cover them.
Add 2 teaspoons of black pepper and 2 teaspoons of allspice.
Seal the jars with bladders and let them sit for two weeks before using.

Recipe from a historical cookbook (Internet Archive).

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.

Pepper + allspicetop 5% of all pairs

Smell alikestrong

Cooked together6,395 recipes

Shared aroma: estragole (anise, licorice).
Pepper + oniontop 11% of all pairs

Smell alikemoderate

Cooked together68,474 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Allspice + oniontop 13% of all pairs

Smell alikemoderate

Cooked together4,270 recipes

Shared aroma: coumarin (sweet, hay).
Vinegar + allspicetop 13% of all pairs

Smell alikemoderate

Cooked together4,548 recipes

Shared aroma: 2-methylbutyl acetate (fruit).
Vinegar + oniontop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).