Why it works: Cider and vinegar are a kitchen classic. They rank in the top 6% of all ingredient pairs, and cooks put them together in 3,431 recipes. Both carry 4-ethyl-2-methoxyphenol, which smells smoky, clove. The science ↓
Green Tomato Catsup
Ingredients
Directions
In a large pot, combine the green tomatoes, onions, cider vinegar, red pepper, salt, mixed spices, and brown sugar.
Bring to a boil, then reduce heat and simmer until the mixture is reduced by half.
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.
-
Cider + vinegartop 6% of all pairsSmell alikemoderateCooked together3,431 recipes
Shared aroma: 4-ethyl-2-methoxyphenol (smoky, clove).
-
Tomato + peppertop 7% of all pairsSmell alikemoderateCooked together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Tomato + oniontop 8% of all pairsSmell alikemoderateCooked together20,633 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Onion + vinegartop 14% of all pairsSmell alikemoderateCooked together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Green tomatoes
- Provide the bulk of the ketchup and its tart, fresh-vegetable body as they break down.
- Onions
- Add savory depth and body that thickens the mixture as it reduces.
- Cider vinegar
- Adds acidity that gives the ketchup its sharp tang and helps preserve it.
- Brown sugar
- Balances the acidity with sweetness and adds caramel notes as it simmers.
- Mixed ground spices
- Supply the aromatic warmth that defines the ketchup's flavour.
The step that matters
Simmering until reduced by half. Long simmering evaporates water and concentrates the vegetables, sugar and vinegar, so the sauce thickens and becomes shelf-stable. Stopping early leaves it thin and watery.
Swap the onion
How well each one fits the dish's main ingredients (tomato, cider, vinegar, pepper, sugar):
- Capsicumfits better
- Mustardfits better
- Cucumberfits better
- Onionthe original
Fit is the average pairing score against tomato, cider, vinegar, pepper, sugar. 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.
You might also like
The 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.
Cider Sauce15 recipes
Wine Sauce (for stewed fruit)186 recipes
Caper Sauce180 recipes
Brown Sauce141 recipes