Name: To Pickle Onions
Ingredients: small white onions; salt; water; strong vinegar; sliced ginger

Why it works: Onion and ginger are a kitchen classic. They rank in the top 9% of all ingredient pairs, and cooks put them together in 7,595 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

To Pickle Onions

Ingredients

Directions

Remove the outer skin from the small white onions.
Soak the onions in a mixture of salt and water for one week, changing the water daily.
Place the soaked onions in a jar and pour boiling saltwater over them.
Cover the jar tightly and let it cool, then drain off the pickle.
Transfer the onions to wide-mouthed bottles and fill them with strong vinegar.
Add a little sliced ginger to each bottle and cork them tightly.

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.

Onion + gingertop 9% of all pairs

Smell alikemoderate

Cooked together7,595 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Onion + vinegartop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).
Vinegar + gingertop 19% of all pairs

Smell alikemoderate

Cooked together5,126 recipes

Shared aroma: isoamyl acetate (banana, pear).