Name: Pepper Catsup
Ingredients: 4 dozen peppers; 2 quarts vinegar; 1 tablespoon salt; 1 tablespoon cloves; 3 tablespoons grated horseradish; 3 garlic cloves, chopped; 5 onions, chopped; additional cold vinegar

Why it works: Garlic and onion match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 29,058 recipes. Both carry furaneol, which smells caramel, strawberry. The science ↓

Pepper Catsup

Ingredients

Directions

Cook the peppers

Boil the peppers in 2 quarts of vinegar until soft.
Strain the mixture and add salt, cloves, horseradish, garlic, and onions.

Finish and bottle

Boil for 30 minutes.
Add a little cold vinegar and bottle the catsup.

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.

Garlic + oniontop 1% of all pairs

Smell alikestrong

Cooked together29,058 recipes

Shared aroma: furaneol (caramel, strawberry).
Pepper + clovetop 5% of all pairs

Smell alikestrong

Cooked together17,451 recipes

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

Smell alikestrong

Cooked together719 recipes

Shared aroma: coumarin (sweet, hay).
Horseradish + oniontop 7% of all pairs

Smell alikestrong

Cooked together1,784 recipes

Shared aroma: coumarin (sweet, hay).
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

What each ingredient does

Peppers: Form the bulk of the catsup and give it its body and main flavor.
Vinegar: Provides acidity that sharpens the flavor and helps the catsup keep.
Onions: Add savory depth and aroma as they cook down into the sauce.
Garlic cloves: Contribute pungent aroma that mellows during the long boil.
Horseradish: Adds sharp, pungent heat that gives the catsup its bite.
Cloves: Contribute warm, aromatic spice notes to the sauce.

Swap the clove

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

Parsleyfits better
Tarragonfits better
Capersfits better
Clovethe original

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

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.