Why it works: Milk and butter are a kitchen classic. They rank in the top 7% of all ingredient pairs, and 81,283 recipes mention both. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓
Tomato Soup
Ingredients
Directions
Boil the stewed tomatoes with the water for 10 minutes.
Add the milk, butter, baking soda, and mustard mixed with a little milk to the tomatoes.
Season with pepper and coarse sea salt to taste.
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.
Photo for illustrative purposes only · Contact us to use it
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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Milk + buttertop 7% of all pairsAroma overlapmoderateMentioned together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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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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Mustard + peppertop 9% of all pairsAroma overlapmoderateMentioned together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Tomato + mustardtop 11% of all pairsAroma overlapmoderateMentioned together2,482 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Flour + buttertop 12% of all pairsAroma overlaplowMentioned together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
Flour and butter share little aroma chemistry, yet 124,287 recipes mention both: they likely work on texture and structure more than aroma.
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Stewed tomatoes
- Form the soup's body and provide its tangy, acidic flavour.
- Milk
- Adds creaminess and softens the tomato's sharpness for a smoother soup.
- Baking soda
- Neutralises tomato acidity, which helps keep the milk from curdling.
- Butter
- Adds fat for richness and a rounder mouthfeel.
The step that matters
Adding the milk and baking soda. Tomatoes are acidic, and heating milk in acid can make it curdle. Baking soda raises the pH and reduces this risk, so it should be stirred in before the milk goes in.
Flavor stand-ins for the mustard
How well each one fits the dish's main ingredients (tomato, flour, milk, butter, egg, pepper):
- Capsicumbetter flavor fit
- Potatobetter flavor fit
- Asparagusbetter flavor fit
- Mustardthe original
Fit is the average pairing score against tomato, flour, milk, butter, egg, pepper. 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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