Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. 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
Stew the tomatoes until soft, then strain them.
If the soup is very sour, add baking soda.
Add stock, sugar, salt, and pepper to the strained tomatoes.
If desired, thicken the soup with flour and butter cooked together.
Prepare and brown the bread
Butter the stale bread slices.
Cut the buttered slices into small squares.
Place the squares in a tin pan, butter side up.
Brown the bread in a 400°F (200°C) oven.
Serve
Serve the browned bread with the soup.
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.
-
Butter + breadtop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
-
Tomato + peppertop 7% of all pairsSmell alikemoderateCooked together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Tomato + breadtop 10% of all pairsSmell alikemoderateCooked together1,013 recipes
Shared aroma: 2-nonenal (fatty, green).
-
Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Sugar + flourtop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
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 flavor of the soup once stewed and strained.
- Baking soda
- Neutralizes acidity in the tomatoes, mellowing a sour soup.
- Stock
- Adds liquid and savory depth to the soup base.
- Flour
- Thickens the soup when cooked together with butter into a roux.
- Butter
- Enriches the thickening roux and adds richness to the bread.
- Stale bread slices
- Become crisp and golden when browned, giving the soup a crunchy contrast.
The step that matters
Adding baking soda. Baking soda neutralizes acid, so adding too much can make the soup taste soapy or flat. Add it only if the soup is very sour, and in small amounts, stirring and tasting as you go.
Swap the tomato
How well each one fits the dish's main ingredients (sugar, pepper, flour, butter, bread):
- Capsicumfits better
- Shallotfits better
- Leekfits better
- Tomatothe original
Fit is the average pairing score against sugar, pepper, flour, butter, bread. 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.
More tomato soup recipes
You might also like
Brown Bread461 recipes
White Bread80 recipes
Tomato Bisque61 recipes
Bread Omelette60 recipesThe free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.