When making a cheese sauce, béchamel, or gravy, you'll often see the recipe requires you to heat a bit of fat, add a similar amount of flour and cook the two for a minute or two before adding the liquid. This is called "making a roux", a technique used to thicken sauces and a good one to master if you're a fan of mac 'n' cheese! Here's what you need to know.
Why a Roux Works
The fat is combined with the starch first to prevent the starch granules from absorbing too much liquid too quickly and clumping together. The coating the fat provides gives you enough time to evenly distribute the starch throughout the liquid for a smooth and lump-free sauce.
Important Things to Remember
- Use a heavy-bottomed, stainless-steel pan so the roux doesn't burn. Avoid using an aluminium pan which can turn your sauce grey.
- For a clump-free sauce, avoid adding a scorching hot liquid to your roux. Instead, you want to heat the starch and liquid slowly to give the starch granules enough time to distribute evenly in your liquid instead of swelling quickly and clumping.
- Starch doesn't thicken fully until near the boiling point, which why the sauce must be brought to a boil. Whisking constantly while heating prevents burning and the heating process cooks the raw taste of the flour out.
- Always follow the proportions as specified in the recipe. A proper roux should be stiff, not runny or pourable. If there is too much fat in the pan, the excess will rise to the surface and make your sauce greasy.
- While a roux can be made with other starches, you'll most commonly see us make it with all-purpose flour. If you're using another starch, the proportions must be adjusted because thickening powers can vary.
Now you know how to properly roux! Test out the technique in any of these favourite recipes.
Macaroni and Four Cheeses
Stove-Top Macaroni and Cheese
Three-Cheese Rotolo with White Sauce
Squash, Spinach and Italian Cheese Cannelloni
Chunky Chicken in Dijon Cheddar Sauce
Chicken Rolls with Chardonnay Sauce
Classic Roast Turkey with Gravy