Why it works: Butter and milk are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓
Tomato Soup
Ingredients
Directions
Prepare the tomatoes
Stew the tomatoes until soft.
Strain the tomatoes through a soup strainer to remove seeds.
Measure 1 pint of the tomato liquid and add salt, pepper, baking soda, and onion.
Heat the mixture slowly on the stove.
Make the white sauce
Heat the milk in a separate saucepan.
Melt the butter in another pan.
Stir in the flour until it becomes bubbly, about 2-3 minutes.
Gradually pour in the heated milk, stirring until smooth.
Combine and serve
Combine the tomato liquid with the white sauce.
Strain the mixture again.
Return the soup to heat.
Serve as soon as steaming hot.
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 their aromas overlap, and how often cooks already put them together.
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Butter + milktop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Tomato + peppertop 7% of all pairsSmell alikemoderateCooked together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Tomato + oniontop 8% of all pairsSmell alikemoderateCooked together20,633 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Pepper + oniontop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
Butter and flour barely smell alike, yet cooks put them together in 124,287 recipes: they 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 body, flavor, and liquid base of the soup.
- Milk
- Forms the liquid base of the white sauce, adding creaminess to the soup.
- Butter
- Adds richness and fat, and is cooked with flour to form the sauce base.
- Flour
- Thickens the butter and milk into a smooth white sauce.
- Baking soda
- Neutralizes some of the tomato's acidity.
The step that matters
Gradually pour in the heated milk, stirring until smooth. Adding cold or all-at-once milk to the hot butter and flour roux can leave lumps, because the starch grains clump before they can disperse evenly. Adding warm milk slowly while stirring lets the starch hydrate smoothly and thicken into a uniform sauce.
Swap the onion
How well each one fits the dish's main ingredients (tomato, pepper, butter, flour, milk):
- Capsicumfits better
- Potatofits better
- Okrafits better
- Onionthe original
Fit is the average pairing score against tomato, pepper, butter, flour, milk. 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.
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