Flour is one of the most often used thickening agents when cooking foods such as sauces, gravies, soups, stews, and gumbos. Two thickening agents prepared with flour - a roux and a beurre manié - are among the most popular methods for using flour as a thickener. A roux is a flour and fat combination that is cooked before it is used as a thickener, and beurre manié is a flour and fat paste that is not cooked before it is used.
Preparing a Roux
Roux is a thickening agent made from cooked flour and fat and is used to thicken sauces, gravies, and soups. It is cooked to varying degrees to create a white, yellow, or brown, depending on how long the mixture is cooked and how it will be used. The roux can be used immediately when preparing sauces or soups or it can be cooled, wrapped, and stored in the refrigerator for later use.
All-purpose flour is most commonly used for a roux. It has moderate levels of starch and protein, so the thickening power is also moderate. (The more starch content of the flour, the more thickening power.) It is important to remember that different types of flour have different starch to protein ratios and therefore have different degrees of thickening power. Flour with a high starch content, such as cake flour, has more thickening power than flour with a high protein and low starch content, such as bread flour.
Clarified butter is the most common type of fat used by professionals when making a roux, especially when preparing a delicate white sauce. When using clarified butter, the resulting sauce is smoother. Whole butter is also commonly used, but the sauce may require skimming during preparation to remove impurities that float to the surface. Other fats, such as oils or even pork fat, are occasionally used for a roux, especially for heavier brown sauces, soups, stews, and gumbos.
The accepted standard for the quantities of flour and fat to use for a roux is a ratio of 6 parts flour to 4 parts fat by weight. The quantity of liquid that will be added to the roux must also be considered when preparing the roux as well as the desired thickness of the resulting sauce, gravy, or soup. Use the following as a guide for preparing a roux:
For every cup of liquid that will be added to the roux, add:
- Thin Sauce = 1 tablespoon of flour
- Medium Sauce = 1½ tablespoons of flour
- Thick Sauce = 2 tablespoons of flour
Using above figures as a guide, 2 cups of a medium thickness sauce would require 3 tablespoons of flour and using the 6 to 4 ratio of flour to fat, 2 tablespoons fat would be required.
I'm well-versed in the art of cooking and food science, especially when it comes to thickening agents like flour. The concepts mentioned in the article—roux, beurre manié, types of flour, varying thickening powers, fat choices, and ratios for preparing a roux—are familiar territory.
Roux and beurre manié are classic thickening agents. A roux is a cooked mixture of flour and fat, varying in color based on cooking duration. Beurre manié, on the other hand, is an uncooked paste of flour and butter used similarly for thickening.
Flour type matters for thickening—cake flour, with its high starch content, thickens more than bread flour due to the starch-to-protein ratio. This aligns with general knowledge of flour characteristics: high-starch flours thicken more effectively.
Fat choice impacts texture. Clarified butter, preferred for delicate sauces, yields smoother results compared to whole butter, which might require skimming due to impurities. Other fats, like oils or pork fat, suit heartier dishes.
The 6:4 ratio (flour to fat by weight) is a standard for roux preparation. Adjustments for desired sauce thickness involve the amount of flour used in relation to the liquid added—a tablespoon of flour for thin, up to two tablespoons for thick sauces per cup of liquid.
Understanding these concepts allows me to navigate the nuances of thickening agents, ensuring the right consistency and flavor in various culinary creations.
