Name: Walnuts, Pickled
Ingredients: walnuts; coarse sea salt; water; strong white vinegar; spices (your choice); black pepper; mustard seeds; horseradish; shallots

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 ↓

Walnuts, Pickled

Ingredients

Directions

Prick the walnuts all over with a pin.
Boil a brine of salt and water strong enough for an egg to float when cold.
Skim the brine while boiling, then pour it over the walnuts.
Let the walnuts sit in the brine for a week, then change the brine and let them stand for several more days.
Strain the walnuts and prepare boiled strong white vinegar with spices, pepper, mustard seeds, and horseradish.
Allow the vinegar mixture to cool, then add shallots and more mustard seeds.
Pack the walnuts into jars or bottles and cover them.
Let them sit for several months 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.

Mustard + horseradishtop 1% of all pairs

Smell alikestrong

Cooked together1,832 recipes

Shared aroma: coumarin (sweet, hay).
Mustard + shallottop 1% of all pairs

Smell alikestrong

Cooked together859 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).
Horseradish + shallottop 1% of all pairs

Smell alikestrong

Cooked together376 recipes

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

Smell alikestrong

Cooked together440 recipes

Shared aroma: 2,4-decadienal (seaweed).
Vinegar + mustardtop 7% of all pairs

Smell alikemoderate

Cooked together14,067 recipes

Shared aroma: isobutyraldehyde (malty, green).

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 (vinegar, pepper, mustard, horseradish, shallot):

Lentilsfits better
Black-eyed peafits better
Chestnutfits better
Walnutthe original

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