Sauce Scaling Calculator

About 120 g of roux per litre of liquid for a medium sauce, which is the classic one part roux to eight parts liquid. Use around 70 g per litre for a thin pouring sauce, 175 g for a thick coating sauce and up to 240 g for a very thick base. Roux is equal weights of flour and fat, so a 120 g roux is 60 g of flour and 60 g of butter. Measure by weight rather than volume, because flour packs unpredictably.

Yes, and by a precise amount. Reduction removes water and adds nothing, so everything dissolved is concentrated by the ratio of the volumes. Reducing a litre to 700 mL concentrates the salt by 1.43×, so a sauce seasoned to 1% arrives at 1.43%. Halve a sauce and you double the salt. This is why professional kitchens use unsalted stock, reduce first and season at the very end.

No — scale it with the finished liquid volume, which is not the same thing when reduction is involved. If you double a recipe but reduce it harder, the finished volume might be far less than double, and thickening for the recipe multiplier would give you glue. Work out what volume you will actually end up with, then apply the grams per litre to that.

They do different jobs. Cornstarch has roughly twice the thickening power by weight, so you need about half as much, and it gives a glossy, translucent finish that suits Asian sauces and fruit fillings. Flour in a cooked roux gives an opaque, matte, richer result and tolerates long simmering, whereas cornstarch can thin out if held hot too long or stirred aggressively after setting.

Because evaporation happens at the surface and the surface did not change. Twice the liquid in the same pan is twice as deep, so the rate of reduction per unit of sauce is halved. Use a wider pan, split the batch across two, or accept a much longer time. The relationship is the same one that governs any scaled-up braise, and the batch cooking calculator covers it in full.

One part roux to eight parts milk by weight, so 120 g of roux — 60 g butter and 60 g flour — per litre of milk. That gives a medium sauce suitable for lasagne or a gratin. For a thinner béchamel to use as a base for a soup, drop to about 70 g per litre; for a croquette or soufflé base where the sauce has to hold its shape, go up to 240 g.

After, essentially always. Reduction multiplies whatever seasoning is already present by the concentration factor, and that factor is easy to underestimate: taking a sauce down by a third is a 1.5× multiplication. Season lightly if you must for balance during cooking, then adjust properly once the sauce has reached its final volume. Use unsalted or low-salt stock for anything you plan to reduce hard.

Either reduce it further, which also concentrates the flavour and the seasoning, or whisk in a beurre manié — equal weights of soft butter and raw flour kneaded to a paste — a little at a time off the boil. The second option thickens without changing the volume or the seasoning much, which makes it the better rescue when the sauce already tastes right. A cornstarch slurry works too but must be slaked in cold water first or it will lump.

Around 30 to 60 mL for a pan sauce served alongside a protein, about 60 mL for a gravy, and 120 mL a head for a pasta sauce where the sauce is a substantial part of the dish. Make perhaps 15% more than the arithmetic suggests: some clings to the pan, some to the spoon, and running out of sauce is a more visible failure than having a little left over.

For the same reason it turned salty — reduction concentrates everything, including things you would rather it did not. Tannic wine becomes harsh, over-browned aromatics become acrid, and tomato acidity sharpens rather than sweetening. The fix is upstream: use a wine you would drink, do not let the fond catch, and taste the liquid before you commit to a long reduction rather than after.