On French Cooking – Thickening Agents Part 2 (2024)

In the previous post, the history and science of thickening agents were explored. The use of a “roux” in French cuisine is critical in producing four out of five of the mother sauces that have been developed by the French culinary arts. In this post OnFrenchCooking will discuss some more food science on thickening agents and how to make the three types of roux; white, blonde and brown. Using French terminology the three names are; roux blanc, roux blond, and roux brun.

More food science regarding thickening agents:

“Natural starches are extracted from roots, tubers, and grains. Each type, no matter the source, contains two basic types of starch: amylase (a long, straight-chained type) and amylopectin (a short, branched-chain type).” (2)

“The characteristics and the way the starch reacts when cooked are related to the proportion of each starch type—amylase and amylopectin—it contains.” (2)

“Grain starches (e.g., wheat flour, corn flour, and oat flour) contain a high amount of amylase and are clear when hot and cloudier when cold. The products they produce are able to be sliced with a knife but deteriorate (become spongy and watery) when frozen. Grain starches thicken just below the boiling point, about 190°F, and do thin when stirred after they are cool. Sauces are opaque hot and cold because flours contain elements other than starch.” (2)

“Root starches (e.g., tapioca and arrowroot) have a higher ratio of amylopectin than grain starches. For example, corn and rice starches can contain up to 99 percent amylopectin. As a result, they are clear in appearance whether hot or cold. They thicken at about 140° to 160°F and freeze and thaw without thinning.” (2)

“Pure starches (cornstarch, tapioca, arrowroot and potato starch)…These pure polysaccharide molecules absorb liquid and swell up efficiently and effectively, thickening all the liquid. However, the application of too high a heat can cause these starch powder thickening agent starch molecules to break down (lose their thickening strength) and cause the sauce or soup to return to a more liquid (low viscous) state.” (2)

Regarding the performance of a roux, the key consideration is the fact that all thickening agents contain starch and all starches break down as they are heated. The heating process reduces their thickening power by the breakdown of their molecular structures.

Photo by Klaus Nielsen: https://www.pexels.com/photo/woman-showing-wheat-flour-in-hands-6287581/

A note on corn flour vs. cornstarch:

There is a distinction on the starches that come from the corn plant. Both have unique thickening properties due to their ratio of amylase and amylopectin. Pure starches are found to have a higher proportion of amylose which acts more effectively at thickening liquids.

“Amylose is hydrolyzed more readily than amylopectin, and the ratio of hydrolysis of amylose to amylopectin may reach 2:1.” (13)

“Corn flouris obtained by grindingentiredried corn kernels into a fine powder. It’s basically very finely ground corn meal. In addition to the starch, it also contains fiber, protein and a small amount of fat.” (3)

“Cornstarchis obtained by extracting the starch from corn grain, specifically from the endosperm of the kernel. It is almost 100% starch, without any fiber, protein, fat or other components.” (3)

Photo by Monstera Production: https://www.pexels.com/photo/plate-with-gentle-marshmallows-and-cream-near-glass-of-cocoa-7144892/

The roux blanc or white roux:

This is the lightest colored of the roux and provides the greatest thickening power of the three types of roux due to it being heated the shortest amount of time. As the starch is heated it loses its thickening power. Its color should be white and have a subtle fragrance. It is important to heat the thickening agent enough to get rid of its unique flavor.

“White roux is cooked for about 5 minutes, just until the flour has lost its raw smell, but before any golden color or toasted aroma develops.” (5)

Photo by Abdurrahim Israfilov: https://www.pexels.com/photo/close-up-of-a-basket-with-shekarbureh-sweet-pastry-in-half-moon-shape-18732597/

The roux blond or blonde roux:

To create the blond roux you simply keep heating the white roux while continuously whisking until it achieves a defined color that could be described as light tan. The fragrance is noticeable and can be described as bread being baked.

“Has a nuttier flavor than white roux…” (8)

“Blond has a yellow tint and smells like freshly baked sugar cookies.” (9)

Photo by Henry Becerra: https://www.pexels.com/photo/milk-chocolates-and-white-chocolates-on-display-4823095/

The roux brun or brown roux:

Once your roux is at the blond state keep heating and whisking until a defined brown color is achieved. The color could be described as a caramel brown shade.

“…Has a nutty flavor, with less thickening power than lighter rouxs.” (8)

“…Brown roux:It takes 15–30 minutes to develop the nutty taste and aroma of a …brown roux. Once it reaches a coppery brown hue, sometimes compared to melted milk chocolate, it’s ready.” (11)

Making the roux is not a difficult process but it can go wrong all to easily. If needed, just toss the failed attempt in the garbage and try again! Have fun exploring the culinary arts and let your passion grow as your scientific understanding of how all this stuff works develops.

This recipe is an example of one way to make a batch of roux. You can tailor the recipe as you desire to meet your needs. You may just want to make a small batch that you utilize immediately for a sauce or soup. Storing a larger batch of roux is recommended so you will have it ready to use on demand.

Photo by neil kelly: https://www.pexels.com/photo/grey-steel-kitchenwares-735338/

Equipment:

1. Saucepan
2. Whisk
3. Spatula
4. Container for storing your finished roux
5. Measuring cup
6. Food scale

Ingredients:

1. All-purpose flour – 1/2 pound sifted
2. Clarified butter – 1/2 pound or about 1 cup

OnFrenchCooking recommends making about 1 pound of roux at a time.

Process:

1. Heat the saucepan to medium heat
2. Add your clarified butter in the saucepan and be sure it is fully melted
3. Add 1 tablespoon of flour at a time and whisk well until fully incorporated before adding another tablespoon of flour
4. Continue this process until all flour is incorporated
5. Keep whisking until the desired color of roux is achieved
6. Use your spatula to scoop the roux into your container.
7. If not being used immediately, allow to cool before refrigeration.

You can store your finished roux in the refrigerator or freeze.

One key consideration when using a roux is to never incorporate a hot liquid into a hot roux and to not incorporate a hot roux into a hot liquid. Either the liquid or roux must be cool before incorporation. Typically you are incorporating a cool roux into a hot liquid such as when making a sauce. Otherwise the roux will become lumpy and that is not going to please your guests! You want a smooth consistency that melds all ingredients together seamlessly.

Thank you for exploring thickening agents and the creation of the “roux”, an essential technique in French culinary arts. In the next series, OnFrenchCooking will be exploring the five mother sauces, four of them utilize a roux. Have fun learning and please share with others your joy of cooking!

Bonne chance dans votre parcours pour devenir un grand chef!

References:

1. https://sesquiotic.com/2014/07/24/roux/ on May 25, 2024
2. https://www.isbe.net/CTEDocuments/FCS-L700032.pdf on May 25, 2024
3. https://theloopywhisk.com/2022/01/15/cornstarch-corn-flour-difference/ on May 25, 2024
4. https://www.thechoppingblock.com/blog/from-white-to-black-breaking-down-roux#:~:text=Blond%20Roux%3A%20Just%20as%20the,the%20flavor%20is%20super%20subtle. on May 25, 2024
5. https://www.allrecipes.com/article/how-to-make-roux/#:~:text=There%20are%20four%20varieties%20of,sauces%2C%20soups%2C%20and%20chowders. on May 25, 2024
6. https://www.emerils.com/121376/blond-roux on May 25, 2024
7. https://www.foodnetwork.com/how-to/packages/food-network-essentials/how-to-make-a-roux on May 25, 2024
8. https://www.masterclass.com/articles/how-to-make-a-roux-step-by-step-guide on May 25, 2024
9. https://raisedonaroux.com/whatsaroux/ on May 25, 2024
10. https://www.tastingtable.com/1107878/why-the-color-of-your-roux-matters/ on May 25, 2024
11. https://www.epicurious.com/expert-advice/how-to-make-and-what-to-do-with-roux-article on May 25, 2024
12. https://www.escoffier.edu/blog/recipes/how-to-make-roux/ on May 25, 2024
13. https://www.sciencedirect.com/topics/chemistry/amylopectin on May 25, 2024