Q. Is there a standard ratio of flour, butter and liquid when making a roux? Each recipe lists different amounts, which makes it difficult when I want to make a cream sauce without following an entire recipe.
There are standard ratios, but the formulas vary based on the heaviness of the completed sauce. There are light, medium and heavy sauces, and the one you need depends on the dish. A thin sauce, for instance, could be used for a cream-based soup, while a heavy one might become something really rich like chicken a la king.
For a thin bechamel, the most milk- or cream-based white sauce, you'd use 1 tablespoon butter and 1 tablespoon flour for 1 cup of milk. For a medium thickness, you'd use 2 tablespoons each of butter and flour to 1 cup milk. For a really thick sauce, you'd use 3 tablespoons each of butter and flour.
The roux is actually the base of starch and fat that is cooked for a short time before the liquid is stirred in. Cooking the starch in fat allows the granules to relax, so they can absorb lots of liquid, creating a suspension that gives the silky texture we think of when we think of a cream sauce.