How to Make a Roux (White, Blond, Brown, and Dark)
Quick steps (10 min)
You need: heavy-bottomed saucepan or Dutch oven, whisk or flat wooden spoon, kitchen scale
A roux is equal weights of fat and flour cooked together into a paste, used to thicken sauces, soups, and gravies. Cook it briefly for a pale roux with strong thickening power, or longer for a nutty brown roux with deep flavour and less thickening.
Why a roux works
Flour is mostly starch. When starch granules are heated in water to roughly 60–70 °C / 140–160 °F and above, they absorb liquid, swell, and burst, releasing long starch molecules that tangle and thicken the sauce. This is starch gelatinization.
Throw dry flour straight into hot liquid and the outside of each clump gelatinizes instantly, sealing dry flour inside: lumps. In a roux, each flour particle is coated in fat first. When the liquid goes in, the fat keeps the particles separate long enough for them to disperse evenly before they swell.
Cooking the roux also toasts the flour, removing its raw, pasty taste. The longer you cook, the more the starches break down into shorter chains (dextrinization) and brown, adding nutty, toasty flavour while reducing thickening power.
Roux colours at a glance
| Roux | Cook time (medium heat) | Colour and smell | Used for |
|---|---|---|---|
| White | 2–3 minutes | Pale, no colour; smells like pie dough | Béchamel, cream soups |
| Blond | 5–8 minutes | Straw to light gold; faintly nutty | Velouté, gravy, chowder |
| Brown | 15–30 minutes | Peanut butter to light chocolate | Espagnole, brown gravy, étouffée |
| Dark | 30–45+ minutes | Dark chocolate, roasted aroma | Gumbo |
Times are a guide; colour and smell are what count. Higher heat is faster but much riskier.
Fat options
- Butter: Classic, rich flavour for white and blond roux. Whole butter's milk solids can scorch during long cooking, so use clarified butter for brown roux.
- Neutral oil: Best for dark roux; won't burn as easily.
- Rendered fat: Bacon fat, duck fat, or meat drippings add flavour, especially for gravy.
How much roux to use
For 250 mL / 1 cup of liquid, using a white or blond roux:
| Consistency | Fat | Flour | Use |
|---|---|---|---|
| Thin | 15 g / 1 tbsp | 15 g / 2 tbsp | Soups |
| Medium | 30 g / 2 tbsp | 30 g / 1/4 cup | Sauces, gravies |
| Thick | 45 g / 3 tbsp | 45 g / 6 tbsp | Soufflé bases, binders |
Brown and dark roux need roughly 1.5–2 times as much for the same thickness.
Steps
- Weigh equal amounts of fat and flour. A scale is most accurate; 30 g of each is a good starting batch for 250 mL of liquid.
- Melt the fat in a heavy-bottomed pan over medium heat.
- Add all the flour at once and whisk until it forms a smooth paste with the texture of wet sand.
- Stir constantly with a whisk or a flat wooden spoon, reaching the corners. The roux will bubble and loosen slightly as it cooks.
- Cook to the colour you need. White: 2–3 minutes. Blond: 5–8. Brown: 15–30. Dark: 30–45. Lower the heat as it darkens.
- Add the liquid gradually. Use either hot roux with cool liquid, or cooled roux with hot liquid. That temperature contrast helps prevent lumps. Pour in about a third, whisk until smooth, then add the rest.
- Bring to a simmer, whisking. Starch doesn't reach full thickness until it's near the boil.
- Simmer at least 5 minutes, longer for big batches, to cook out any raw flour flavour. Season at the end.
Chef Fizz says: Making a dark roux? Put your phone away and have everything else chopped first. One distracted minute can turn chocolate brown into black, and there's no un-burning it.
Common mistakes and fixes
Lumpy sauce. The liquid went in too fast, or both roux and liquid were hot. Whisk hard; if lumps remain, use an immersion blender or strain through a sieve.
Burnt roux. Black specks and a bitter, acrid smell mean it's burnt. You can't save it. Throw it out and start again at lower heat.
Sauce tastes floury. It wasn't simmered long enough after adding liquid. Keep simmering for 5–10 more minutes.
Sauce isn't thick enough. Simmer longer to reduce, or whisk in a little beurre manié (equal parts soft butter and flour kneaded together).
Sauce is too thick. Whisk in more warm liquid a splash at a time.
Roux split and looks greasy. Too much fat for the flour. Whisk in a spoonful more flour and keep cooking.
Gluten-free roux
Sweet rice flour makes an excellent gluten-free roux using the same ratio by weight. Cornstarch and arrowroot don't form a proper roux; use them as a slurry instead.
Questions
What is the ratio for a roux?
Equal weights of fat and flour. About 30 g (2 tbsp) butter plus 30 g (1/4 cup) flour thickens 250 mL (1 cup) of liquid to a medium sauce consistency.
Why does a darker roux thicken less?
Long cooking breaks down the flour's starch through dextrinization, so it absorbs less water. A dark roux can have roughly half the thickening power of a white roux, so you need more of it.
Can you make a roux with oil instead of butter?
Yes. Oil is standard for dark Cajun roux because it has no milk solids to burn. Use a neutral oil with a high smoke point.
How do you fix a lumpy roux sauce?
Whisk vigorously, and if lumps remain, blend the sauce with an immersion blender or press it through a fine sieve.
Can you make roux ahead of time?
Yes. Cooked roux keeps in a sealed container in the fridge for about 2 weeks or frozen for several months. Break off what you need and whisk into hot liquid.