Why it works: Potato and onion are a kitchen classic. They rank in the top 3% of all ingredient pairs, and cooks put them together in 9,023 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Potato Soup
Ingredients
Directions
Prepare the potatoes
Cook the potatoes in salted water with the onion until soft.
Mash the potatoes smooth and rub through a fine sieve.
Make the soup
Scald the milk with the celery, then remove the celery.
Cream together the butter and flour, then add to the milk.
Add the prepared potatoes to the milk and season with salt and pepper.
Bring to a boil and 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.
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.
-
Potato + oniontop 3% of all pairsSmell alikemoderateCooked together9,023 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Celery + peppertop 5% of all pairsSmell alikestrongCooked together16,012 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
-
Potato + celerytop 7% of all pairsSmell alikemoderateCooked together2,047 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
-
Milk + buttertop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
-
Onion + celerytop 7% of all pairsSmell alikemoderateCooked together18,518 recipes
Shared aroma: guaiacol (smoky, sweet).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Potatoes
- Break down into a smooth, thick body that gives the soup its texture.
- Milk
- Forms the liquid base of the soup and carries the other flavors.
- Butter and flour
- Cooked together into a roux that thickens the milk.
The step that matters
Adding the butter and flour to the milk. Flour clumps if it meets liquid unevenly. Creaming it with butter first coats the starch grains so they disperse, and the milk should be hot enough for the starch to thicken it smoothly.
Swap the celery
How well each one fits the dish's main ingredients (potato, milk, onion, pepper, butter, flour):
- Parsleyfits better
- Thymefits better
- Garlicfits better
- Celerythe original
Fit is the average pairing score against potato, milk, onion, pepper, butter, flour. 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 potato soup recipes
You might also like
The 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.

Potato Croquettes255 recipes
Cream of Celery Soup113 recipes
Potato Rolls78 recipes
Potato Chips53 recipes