Sauce Thickening Calculator — Roux, Slurry & Reduction
Calculate exact ratios for thickening sauces and gravies — roux, cornflour slurry, beurre manié, or reduction. Get the right consistency every time.
Sauce Thickening Guide
Thickener Ratios
Standard ratios by method (per 500mL liquid): Roux: light: 25g butter + 25g flour. Medium: 35g + 35g. Thick: 50g + 50g. Cornflour slurry: light 15g, medium 25g, thick 40g. Arrowroot: same as cornflour but produces clearer, glossier sauces (no opacity from starch granules). Beurre manié: equal parts flour and butter mixed cold and added by spoonful at end. Egg yolk liaison: 2-3 yolks per 500mL. Tempering essential — add hot liquid to yolks gradually to prevent scrambling. Each method gives a diff
Roux Method
The classical thickener. White roux: cook just 1-2 minutes — for béchamel, velouté. Blonde roux: cook 3-5 minutes — slight nutty flavour. Brown roux: 10-30 minutes for gumbo, classic French brown sauces. Method: melt butter, add flour, cook (stirring constantly) to your desired colour. Add hot liquid slowly, whisking continuously. Bring to simmer — sauce will thicken as starches gelatinise. Common mistake: not cooking the roux long enough (sauce has raw flour taste). Cook roux at least 2-3 minut
Cornflour and Slurry
Cornflour (cornstarch in US) is twice as powerful as flour by weight. Use half the quantity. Always mix with cold water first (the slurry) — never add directly to hot liquid (forms instant lumps). Add slurry to simmering liquid, stir continuously, simmer 1-2 minutes to remove starchy taste. Cornflour-thickened sauces: clearer than roux. Best for Asian sauces, fruit sauces, gravies. Limitations: do not reheat repeatedly (sauce thins). Do not boil vigorously after thickening (breaks the gel). Free
Reduction and Finishing
Reduction: simmer to evaporate water, concentrating flavours and thickening through reduced volume. Time: 10-30 minutes depending on quantity. Stock reductions are central to classical French sauces. The body comes from gelatin in the stock (especially veal stock). Cannot reduce a stock that has not been made properly — gelatin must be present. Finishing techniques: monter au beurre (mounting with butter) — add cold butter at end. Don't boil after — emulsion breaks. Cream finish: add at end, bri
Recommended for this calculator