Name: To Pickle English Walnuts
Ingredients: young walnuts; boiling water; coarse sea salt; whole pepper; cloves; garlic; mustard seed; horseradish (scraped and dried); strong cold vinegar

Why it works: Mustard and horseradish match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 1,832 recipes. Both carry coumarin, which smells sweet, hay. The science ↓

To Pickle English Walnuts

Ingredients

Directions

Gather young walnuts that can be easily pierced with a pin.
Pour boiling water mixed with coarse sea salt over the walnuts and let them soak for nine days, changing the water every third day.
After nine days, remove the walnuts and place them on dishes in the air for a few minutes, turning them to prevent blackening.
In a pot, layer the walnuts with whole pepper, cloves, a little garlic, mustard seed, and dried horseradish.
Cover the walnuts with strong cold vinegar.

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.

Mustard + horseradishtop 1% of all pairs

Smell alikestrong

Cooked together1,832 recipes

Shared aroma: coumarin (sweet, hay).
Pepper + clovetop 5% of all pairs

Smell alikestrong

Cooked together17,451 recipes

Shared aroma: ethyl octanoate (fruity, wine).
Garlic + horseradishtop 5% of all pairs

Smell alikestrong

Cooked together719 recipes

Shared aroma: coumarin (sweet, hay).
Garlic + mustardtop 6% of all pairs

Smell alikestrong

Cooked together4,053 recipes

Shared aroma: linalool (floral, citrus).
Clove + horseradishtop 7% of all pairs

Smell alikestrong

Cooked together1,245 recipes

Shared aroma: coumarin (sweet, hay).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

Swap the walnut

How well each one fits the dish's main ingredients (pepper, clove, garlic, mustard, horseradish, vinegar):

Lentilsfits better
Chickpeafits better
Beansfits better
Walnutthe original

Fit is the average pairing score against pepper, clove, garlic, mustard, horseradish, vinegar. Candidates are from the same food group and used in at least 100 recipes.