Professional technique:the foundation of every classic sauce
Equal parts butter and flour by weight: the foundation of bechamel, veloute, and espagnole. Roux blanc is cooked for 1-2 minutes, roux brun up to 45 minutes for maximum flavour depth and minimum thickening power.
In brief
Roux is a heated mixture of equal parts fat and flour (1:1 by weight) that serves as a thickening agent for sauces, soups, and stews. The starch in the flour gelatinises when heated and absorbs liquid, causing the sauce to thicken.
- Ratio: 60 g butter + 60 g flour per 1 litre of liquid (Escoffier, 1903)
- Three stages: blanc (1-2 min), blond (5-8 min), brun (15-45 min)
- Thickening power decreases with cooking time due to dextrinisation of the starch (McGee, 2004)
- Golden rule: add cold roux to hot liquid or hot roux to cold liquid
Three types of roux
Roux Blanc
Roux blanc is cooked for 1-2 minutes over medium-high heat until the raw flour smell disappears but the colour remains cream-white. This is the roux with the highest thickening power: the starch is fully gelatinised but not dextrinised. Used for bechamel, veloute, and white sauces. The CIA (2011) recommends cooking the roux for at least 1 minute to eliminate the raw flour taste, but longer than 3 minutes already reduces thickening power.
Examples: Bechamel, veloute, mornay, soubise
Roux Blond
Roux blond is cooked for 5-8 minutes until a light golden colour and nutty aroma develop through the Maillard reaction. Thickening power is approximately 20-25% lower than roux blanc due to partial dextrinisation. Used for chicken and veal veloute, as well as bisque. The Larousse Gastronomique (2001) describes the colour as "gold like ripening grain" as a quality benchmark.
Examples: Chicken stock veloute, bisque, sauce supreme
Roux Brun
Roux brun is cooked for 15-45 minutes over moderate heat with constant stirring until a dark brown colour and intense, nutty flavour develop. Thickening power is 40-50% lower than roux blanc (McGee, 2004) due to extensive dextrinisation of the starch. Consequently, a larger quantity of roux is needed for the same thickening effect. Classic in gumbo (Cajun), espagnole sauce, and demi-glace. Note: burnt roux (black) is unusable and bitter.
Examples: Espagnole, demi-glace, gumbo
Auguste Escoffier, Le Guide Culinaire (1903); CIA, The Professional Chef 9th ed. (2011); Harold McGee, On Food and Cooking (2004)
The science behind roux
Starch gelatinisation
Wheat starch gelatinises at 62-68 °C: granules absorb water and swell into a viscous network. Below 62 °C the roux remains floury and tastes raw. Above 80 °C the granules rupture and viscosity drops slightly.
Cold-hot rule
Always add cold roux to hot liquid OR hot roux to cold liquid. Both hot at the same time causes instant gelatinisation at the surface and lumps. CIA (2011): whisk the roux into a small amount of hot liquid before adding it to the pan.
Dextrinisation and Maillard
Above 120 °C long starch polymers break down into shorter dextrins: thickening power drops, nutty aroma increases. The Maillard reaction between amino acids and sugars produces the brown colour. McGee (2004): optimal Maillard temperature for flour is around 150-165 °C surface temperature.
Step-by-step method
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1
Weigh equal parts
Weigh butter and flour in a 1:1 ratio by weight on a precision scale. For 1 litre of sauce: 60 g butter + 60 g flour.
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2
Melt butter over medium-high heat
Melt the butter in a heavy saucepan over medium-high heat. Wait until the foam subsides and the butter becomes clear, but not brown.
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3
Add flour all at once
Add all the flour to the butter at once and stir immediately with a wooden spoon or whisk into a smooth paste without lumps.
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4
Cook the roux to the desired stage
Stir continuously: blanc 1-2 min (cream-white), blond 5-8 min (golden yellow), brun 15-45 min (dark brown). Ensure even heat distribution.
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5
Check for raw flour smell
Smell the roux: a raw floury smell means it is not yet done. The smell should be nutty-neutral for blanc, or distinctly nutty for blond and brun.
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6
Add liquid following the cold-hot rule
Add cold liquid to hot roux or hot liquid to cooled roux. Whisk vigorously to prevent lump formation.
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7
Bring to a boil and check binding
Bring the sauce slowly to a boil while continuing to stir. Only at 62-68 °C does the starch fully gelatinise and the sauce reach its maximum thickness.
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8
Simmer for another 10-15 minutes on low heat
Let the sauce simmer gently for another 10-15 minutes after boiling to eliminate any residual raw starch flavour and fully bind the sauce.
HACCP and food safety for roux
The FDA (2016) warned following outbreaks that raw wheat flour can harbour E. coli O157:H7 and Salmonella. Roux must be actively cooked for a minimum of 1-2 minutes (>70 °C internally) for safe consumption. Never taste raw flour mixtures.
Boiling roux splatters: use a tall pan. Hot-holding of roux-based sauces: minimum 65 °C (NVWA, 2021). No sauce should remain in the danger zone of 10-65 °C for more than 2 hours. Cooling: from 65 °C to 4 °C within 2 hours (EU 852/2004).
Wheat flour/gluten is a mandatory declarable allergen (EU 1169/2011, Annex II). Use separate bowls for gluten-free preparations. Gluten-free roux: rice flour, cornstarch, or arrowroot. Label preparations clearly.
Roux per sauce type: ratios and cooking times
| Sauce | Roux type | Roux per litre | Cooking time roux | Thickening power |
|---|---|---|---|---|
| Bechamel | Blanc | 60-70 g | 1-2 min | Maximum |
| Veloute | Blond | 65-75 g | 5-8 min | High (-20%) |
| Espagnole | Brun | 90-110 g | 20-45 min | Medium (-45%) |
| Gumbo roux | Brun | 120 g | 30-45 min | Low (-50%) |
| Thickened soup | Blanc | 40-50 g | 1-2 min | Maximum |
CIA, The Professional Chef 9th edition (Wiley, 2011); Escoffier, Le Guide Culinaire (1903)
Food cost of roux
- Roux is the most cost-effective thickening agent: butter + flour costs approximately EUR 0.15-0.25 per portion
- Roux brun has 40-50% less thickening power: use proportionally more for the same binding (higher cost)
- Alternative: cornstarch is 3-4x cheaper but adds no flavour; choose roux for flavour-carrying preparations
- Clarified butter (ghee) prevents scorching at higher temperatures for roux brun, but costs 30-40% more
- Batch production: roux blanc keeps 5-7 days refrigerated at 4 °C; make larger quantities for efficiency
Frequently asked questions
Why does my roux form lumps when I add the liquid?
How much roux do I need per litre of sauce?
Can I make roux in advance and store it?
What is the difference between roux and beurre manie?
May I use olive oil or another oil instead of butter?
How do I know if the roux is cooked enough to eliminate the flour taste?
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Applying the techniques described requires professional expertise and training. KitchenNmbrs is not liable for damage, injury, illness or loss resulting from the application of information from this website without adequate professional guidance or verification. Every kitchen, every product and every environment is different: always apply your own professional judgement.
Food safety & HACCP
The HACCP guidelines, temperatures and storage advice on this page are based on Codex Alimentarius (WHO/FAO) as the global baseline standard and EU Regulation 852/2004. Local laws and regulations may differ. Always consult your national food safety authority for the applicable standards in your region:
- Netherlands: NVWA (nvwa.nl)
- Belgium: FAVV (favv-afsca.be)
- Germany: BfR (bfr.bund.de)
- United Kingdom: FSA (food.gov.uk)
- United States: FDA (fda.gov) — FDA Food Code
- EU general: EU Regulation (EC) 852/2004 on food hygiene
- International: Codex Alimentarius CAC/RCP 1-1969 (revised 2020)
Allergens & dietary information
Allergen information is indicative. When in doubt about allergens in preparations, always contact the supplier or a certified allergological adviser. KitchenNmbrs accepts no liability for allergic reactions or diet-related harm.
Copyright & sources
All sources mentioned (Escoffier, McGee, CIA Professional Chef, etc.) are the property of their respective publishers and authors. KitchenNmbrs cites these works in accordance with fair use for informational purposes. The source attribution at the bottom of each technique page is not a complete bibliography but an indication of primary sources consulted.
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- Auguste Escoffier — Le Guide Culinaire (Flammarion, 1903; reprint Wiley, 2011)
- CIA (Culinary Institute of America) — The Professional Chef, 9th edition (Wiley, 2011)
- Harold McGee — On Food and Cooking (Scribner, 2004) — dextrinisation and starch chemistry
- FDA Food Safety — Raw Flour and Bacteria (2016, update 2023) — E. coli O157:H7 risk
- EU Regulation 852/2004 — Food hygiene and cooling protocols
