There is an age-old debate that asks the question “Who wants lumpy gravy?” and usually the answer is “Not me!” In this article I will teach you the easiest and most fool-proof way to get smooth gravy, as well as the neat trick to thickening up any liquid you want.
First, let’s talk about the word “roux”. Roux comes from the French word “rous” meaning “reddish brown”. It originally referred to clarified butter combined with flour and cooked till dark to flavor and thicken four of the five mother sauces – Tomato, Brown (Espagnole), Hollandaise*, Bechamel and Veloute. Today a roux consists of fat mixed with flour and cooked to any of four levels of darkness.
A white roux is the most commonly used for thickening soups/sauces. White roux is simply butter and flour combined into a paste or dough-like substance to which the liquid is added immediately. The next level up is called a blond roux, which is the same combination of flour and fat, but it is cooked slightly longer before adding the liquid. This provides more flavor, but does not affect the thickening power of the roux. The third type of roux is called a medium or peanut-butter roux, due to the appearance of the mixture. It is cooked for even longer than blond roux, giving it a nutty flavor and a color similar to that of peanut butter. The darkest type of roux is called brick or black roux, again referring to the color of the substance. Black roux is cooked for a long time until it turns reddish brown and emits a odor akin to almost-burnt popcorn. Black roux is used mainly in Cajun cooking, especially gumbo.
Take equal amounts butter (or margarine) and flour (IE, 2 ounces of each)
Melt the butter till completely liquefied
Whisk in flour till the mixture resembles dough, cook to desired level (white/blond/medium/black)
Add your liquid (broth, stock, etc.) in small amounts
The liquid added to the roux should be room temperature or colder. Adding a hot liquid to a hot roux will prevent emulsification and you will end up with a lumpy sauce! Conversely, adding a cold liquid to a cold roux will also prevent proper homogenization.
In the event that you have a soup or some sort of liquid that you would like to thicken once it has been finished, there is an alternative to the cornstarch-water slurry that many people use. This option is called “beurre manie” which means “kneaded butter” in French. A beurre manie is also equal parts flour and butter, however, the flour is kneaded into the butter to form dough. To thicken your sauce, slowly add pea-sized bits of this dough to the liquid while continuously whisking until desired thickness is achieved. Once again, make sure your liquid is hot – not boiling but close to it – and make sure the beurre manie is room temperature or colder.
Both roux and beurre manie can be made and stored up to three days under refrigeration. To reuse pre-made roux, heat it up, because it will become a solid under refrigeration.
* Roux is never added to Hollandaise due to the fragile nature of the yolk-acid emulsion.