Roux (pronounced ROO) is a mixture of flour and fat, which is commonly used to thicken sauces.
Most commonly used in French cuisine, it is also one the ingredients in three French mother sauces, namely béchamel sauce, velouté sauce, and espagnole sauce.
This makes it one of the basic culinary skills that every chef should know. It provides the base for a dish where other ingredients are eventually added to it, and is also a thickening agent for gravy, sauces, soups and stews.
The flour used can be a choice of either butter, bacon dripppings or lard. Equal parts of flour is then added to the same amount of melted fat or oil on the stove top and blended until smooth.
There are three types of roux: white, blonde and brown. What makes them different is the amout of time that they are cooked for, thus resulting in three different level of browness.
White roux is only cooked long enough to eliminate the flour's raw flavor, about 2 to 5 minutes. It has the most thickening power and is used in making white sauce.
Blonde roux is caramel cooked for about 10 minutes to make velouté sauce and can be used in any recipe that calls for white roux. This has a nuttier flavor..
Brown roux is the darkest of the lot and is the result of being cooked for as long as 30 minutes. For this, it needs to be stirred continuously. The use of vegetable oil instead of butter is also preferred. It is also the roux with the least thickening power but it deeply flavorful and suitable for use in Cajun dishes.
There is also dry roux, which is basically toasted flour. It can be done in a skillet on the stovetop, or baked at 177ºC in the oven for about 25 minutes. The end result should be a nice and even brown color.
When it comes to making bread, roux is also used to produce a loaf that's lighter, that has a more tender crumb and a longer shelf life. Unlike conventional roux, this roux is made of flour and water, but milk can also be used.
This water roux aka tangzhong is a mixture that is heated to 65°C, at which point the flour becomes gelatinized and forms an unflavored translucent pudding-like roux. It is then added to the remaining liquids in the yeast bread recipe.
During baking, the water roux will help retain moisture in the bread, giving rise to the fluffiest bread ever.
