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 ↓
Brown and White Thickening, or Roux
Ingredients
Directions
Ensure the flour is thoroughly dry and sift it.
Squeeze the butter in a cloth to remove as much moisture as possible.
Melt the butter in a stew-pan until it runs to oil.
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 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 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
- Flour
- Its starch thickens the melted fat and gives the roux its body once cooked.
- Butter
- Its fat coats the flour particles so they cook evenly and thicken without lumping.
The step that matters
Squeezing the butter dry. Water left in the butter spatters in hot fat and turns to steam, which can make the roux uneven or lumpy. Removing it keeps the fat clean for cooking the flour.
“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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