Name: Pickled Walnuts
Ingredients: green walnuts; coarse sea salt; water; cider vinegar; black pepper; ginger; mustard seed; horseradish

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 ↓

Pickled Walnuts

Ingredients

Directions

Gather green walnuts that are small enough to fit a pin into them.
Wipe the walnuts and place them in a cold brine of salt and water strong enough to float an egg.
Let them soak for six days, then change the brine and soak for three more days.
Drain the walnuts and pour over them a cold pickle made from cider vinegar, black pepper, ginger, mustard seed, and horseradish, all boiled together.
Allow the pickled walnuts to sit for six months before consuming.

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).
Cider + vinegartop 6% of all pairs

Smell alikemoderate

Cooked together3,431 recipes

Shared aroma: 4-ethyl-2-methoxyphenol (smoky, clove).
Vinegar + mustardtop 7% of all pairs

Smell alikemoderate

Cooked together14,067 recipes

Shared aroma: isobutyraldehyde (malty, green).
Walnut + horseradishtop 8% of all pairs

Smell alikestrong

Cooked together259 recipes

Shared aroma: coumarin (sweet, hay).
Walnut + mustardtop 9% of all pairs

Smell alikestrong

Cooked together849 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).

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 (cider, vinegar, pepper, ginger, mustard, horseradish):

Beansfits better
Sesamefits better
Lentilsfits better
Walnutthe original

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