Why it works: Tomato and pepper are a kitchen classic. They rank in the top 7% of all ingredient pairs, and 17,923 recipes mention both. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Tomato Sauce
Ingredients
Directions
Prepare
Peel and slice the tomatoes.
Chop the sweet peppers and onions finely.
Cook and seal
Combine all ingredients in a large pot.
Simmer for 2 hours, or until thick.
Bottle and seal the sauce.
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 aroma chemistry they share, and how many recipes mention both.
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Tomato + peppertop 7% of all pairsAroma overlapmoderateMentioned together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Tomato + oniontop 8% of all pairsAroma overlapmoderateMentioned together20,633 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Pepper + oniontop 11% of all pairsAroma overlapmoderateMentioned together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + vinegartop 14% of all pairsAroma overlapmoderateMentioned together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
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Pepper + vinegartop 14% of all pairsAroma overlapmoderateMentioned together27,814 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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 break down into a thick, flavorful base as they simmer.
- Sweet peppers
- Add body and mild sweetness, softening into the sauce during the long simmer.
- Onions
- Add savory depth and aroma, and soften into the sauce as it cooks.
- Vinegar
- Adds acidity that brightens the sauce and helps preserve it for bottling.
- Sugar
- Balances the acidity of the vinegar and tomatoes with sweetness.
The step that matters
Simmer until thick. Tomatoes and peppers release water as they cook, so the sauce thickens slowly over a long simmer. Stopping too early leaves it thin and watery, which can affect how well it keeps after bottling.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (tomato, pepper, sugar, vinegar):
- Capsicumbetter flavor fit
- Cucumberbetter flavor fit
- Mustardbetter flavor fit
- Onionthe original
Fit is the average pairing score against tomato, pepper, sugar, vinegar. Candidates are from the same food group and used in at least 100 recipes. This compares flavor only: it does not check the job the ingredient does in the dish (bulk, moisture, acidity, structure).
“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.
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