Why it works: Mustard and allspice match in chemistry and in kitchens. They rank in the top 2% of all ingredient pairs, and cooks put them together in 1,928 recipes. Both carry methyleugenol, which smells clove, spice. The science ↓
Tomato Catsup
Ingredients
Directions
Combine skinned tomatoes, salt, black pepper, mustard, allspice, and red pepper in a pot.
Add enough sharp vinegar to make 2 quarts of catsup.
Simmer the mixture slowly for 3 to 4 hours.
Strain through a wire sieve if desired.
If you like, add garlic juice after simmering and once the mixture has cooled.
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 + allspicetop 2% of all pairsSmell alikestrongCooked together1,928 recipes
Shared aroma: methyleugenol (clove, spice).
-
Tomato + garlictop 3% of all pairsSmell alikemoderateCooked together14,076 recipes
Shared aroma: furaneol (caramel, strawberry).
-
Pepper + allspicetop 5% of all pairsSmell alikestrongCooked together6,395 recipes
Shared aroma: estragole (anise, licorice).
-
Mustard + garlictop 6% of all pairsSmell alikestrongCooked together4,053 recipes
Shared aroma: linalool (floral, citrus).
-
Tomato + peppertop 7% of all pairsSmell alikemoderateCooked together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Tomatoes
- Form the bulk of the sauce and provide its body, moisture and base flavour.
- Vinegar
- Adds sharpness that balances the sweetness of the reduced tomatoes and helps preserve the sauce.
- Mustard
- Adds sharp, pungent flavour that rounds out the tomato taste.
- Red pepper
- Adds heat and a background bite to the sauce.
The step that matters
Simmer slowly for 3 to 4 hours. Long, gentle simmering evaporates water and concentrates the tomato's sugars and flavour, thickening the sauce. Too hot a heat can scorch the bottom of the pot and burn the flavour, so the mixture should be stirred and kept at a slow simmer.
Swap the garlic
The recipe marks garlic as optional. How well each one fits the dish's main ingredients (tomato, pepper, mustard, allspice, vinegar):
- Tarragonfits better
- Thymefits better
- Dillfits better
- Garlicthe original
Fit is the average pairing score against tomato, pepper, mustard, allspice, vinegar. 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.
More tomato ketchup recipes
You might also like
Tomato Soup526 recipes
Cream of Tomato Soup107 recipes
Tomato Bisque61 recipes
Cream Tomato Soup28 recipesThe free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.