Name: Pickled Walnuts
Ingredients: walnuts; brine (same strength as for cucumbers); shafts (herbs or spices); mustard seed

Why it works: Cucumber and mustard match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 2,281 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Pickled Walnuts

Ingredients

walnuts
brine (same strength as for cucumbers)
shafts (herbs or spices)
mustard seed

Directions

Prick each walnut with a fork; discard any that are too hard.
Soak the walnuts in brine for nine days, changing the brine every third day.
Simmer the walnuts in the last brine in a saucepan.
Drain the walnuts in a colander and let them air dry on a flat surface for one to two days until they turn black.
Prepare a pickle similar to cucumber pickle, adding a few shafts and mustard seed.
Pack the walnuts into jars or bottles, filling them three-quarters full with the pickle.
Seal the jars with corks and cover with bladder or leather.

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.

Cucumber + mustardtop 3% of all pairs

Smell alikestrong

Cooked together2,281 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Walnut + cucumbertop 6% of all pairs

Smell alikestrong

Cooked together380 recipes

Shared aroma: 2-nonenal (fatty, green).
Walnut + mustardtop 9% of all pairs

Smell alikestrong

Cooked together849 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).