Why it works: Flour and butter are a kitchen classic. They rank in the top 12% of all ingredient pairs, and cooks put them together in 124,287 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓
Tomato Soup
Ingredients
Directions
The book says “a quick oven”. The 400°F (200°C) in the steps is the modern equivalent, not the book's own figure.
Make the soup
Combine tomatoes and hot water in a pot and bring to a boil.
In a bowl, mix flour, butter, and a tablespoon of the tomato mixture.
Stir the flour mixture into the boiling tomatoes.
Add salt and sugar, and boil for 15 minutes.
Rub the soup through a sieve and serve with toasted bread.
Toast the bread
Cut the bread into thin slices, butter them, cut into small squares, and place buttered side up in a pan.
Brown the bread in a 400°F (200°C) oven.
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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Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Flour + sugartop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
-
Butter + sugartop 17% of all pairsSmell alikemoderateCooked together98,233 recipes
Shared aroma: guaiacol (smoky, sweet).
-
Tomato + buttertop 22% of all pairsSmell alikemoderateCooked together6,918 recipes
Shared aroma: 3-hexenal (apple, fruity).
-
Tomato + flourtop 22% of all pairsSmell alikemoderateCooked together7,065 recipes
Shared aroma: isobutyraldehyde (malty, green).
Flour and butter 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 and flavour of the soup.
- Flour
- Thickens the soup as it cooks, giving it body.
- Butter
- Adds richness and a smooth fat to the thickened soup.
The step that matters
Stirring the flour mixture into the boiling tomatoes. Flour mixed with fat and a little liquid first disperses evenly; dumping it in dry or clumped leaves lumps, because starch granules clump when they hit hot liquid without being separated.
Swap the tomato
How well each one fits the dish's main ingredients (flour, butter, sugar):
- Arrowrootfits better
- Shallotfits better
- Sweet potatofits better
- Tomatothe original
Fit is the average pairing score against flour, butter, 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.
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