Why it works: Butter and milk 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 ↓
Cream-of-Tomato Soup
Ingredients
Directions
Prepare the tomatoes
Stew the tomatoes slowly for 30 minutes to 1 hour.
Strain the tomatoes and add baking soda while hot.
Make the soup
In a separate pan, make a white sauce using butter and flour.
Add the strained tomato juice to the white sauce.
Serve
Serve immediately.
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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Butter + milktop 7% of all pairsAroma overlapmoderateMentioned together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Flour + buttertop 12% of all pairsAroma overlaplowMentioned together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + milktop 14% of all pairsAroma overlaplowMentioned together78,219 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Tomato + milktop 15% of all pairsAroma overlapmoderateMentioned together2,226 recipes
Shared aroma: 1-octen-3-one (mushroom, metallic).
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Tomato + buttertop 22% of all pairsAroma overlapmoderateMentioned together6,918 recipes
Shared aroma: 3-hexenal (apple, fruity).
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
- Tomatoes
- Provide the main flavour and acidic base of the soup.
- Butter
- Adds richness and helps form the white sauce.
- Flour
- Thickens the butter and milk into a smooth white sauce.
- Milk
- Creates the creamy body and mild sweetness of the soup.
- Baking soda
- Neutralises tomato acidity, which helps keep the milk from curdling.
The step that matters
Adding the strained tomato juice to the white sauce. Tomatoes are acidic, and acid can cause milk proteins to curdle or separate when heated. Baking soda, added to the hot tomatoes, neutralises much of that acidity, which helps the soup stay smooth.
Flavor stand-ins for the white pepper
How well each one fits the dish's main ingredients (tomato, flour, butter, milk):
- Cinnamonbetter flavor fit
- Jalapenobetter flavor fit
- Capersbetter flavor fit
- White pepperthe original
Fit is the average pairing score against tomato, flour, butter, milk. 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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