Name: Keeping Mustard
Ingredients: 3 ounces salt; 1 quart boiling water; 2 ounces scraped horseradish; flour of mustard

Why it works: Horseradish and mustard 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 ↓

Keeping Mustard

Ingredients

3 ounces salt
1 quart boiling water
2 ounces scraped horseradish
flour of mustard

Directions

Dissolve salt in boiling water.
Pour the hot solution over the scraped horseradish.
Cover the jar closely and let it stand for 24 hours.
Strain the mixture.
Gradually mix in flour of mustard until the desired thickness is achieved.
Transfer to wide-mouthed bottles and cork 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.

Horseradish + mustardtop 1% of all pairs

Smell alikestrong

Cooked together1,832 recipes

Shared aroma: coumarin (sweet, hay).
Horseradish + flourtop 10% of all pairs

Smell alikestrong

Cooked together743 recipes

Shared aroma: isobutyraldehyde (malty, green).
Flour + mustardtop 13% of all pairs

Smell alikemoderate

Cooked together5,066 recipes

Shared aroma: isobutyraldehyde (malty, green).