A roux is a fundamental cooking technique used to thicken soups, sauces, and gravies. It’s made by cooking butter and flour together, creating a smooth base that helps add both texture and flavor to many dishes. But what is the correct butter-to-flour ratio for roux? In this guide, we’ll break down the best proportions, different types of roux, and how to use them properly.
What Is Roux?
A roux is a mixture of fat (typically butter) and flour, cooked together before adding liquid. It acts as a thickening agent in béchamel sauce, gumbo, gravy, and creamy soups. The type of roux you make depends on how long you cook it and what dish you’re preparing.
Perfect Butter-to-Flour Ratio for Roux
The standard ratio for making roux is 1:1 by weight. This means:
- 1 ounce of butter (or other fat) to 1 ounce of flour
- 2 tablespoons of butter to 2 tablespoons of flour
This balance ensures the roux is smooth and effective at thickening. If you use too much flour, the roux can become clumpy; too much butter, and it might not thicken properly.
Adjusting the Ratio for Different Textures
- Thinner roux: Use more butter for a looser consistency.
- Thicker roux: Use more flour to create a paste-like texture.
Types of Roux and Their Uses
Roux is categorized based on how long it’s cooked. Each type has a different flavor, color, and thickening ability.
1. White Roux
- Cooking time: 2-3 minutes
- Color: Pale, off-white
- Best for: Béchamel sauce, cheese sauces, soups
White roux has a mild flavor and is great for dishes where you don’t want a strong taste from the thickener.
2. Blonde Roux
- Cooking time: 5-7 minutes
- Color: Light golden
- Best for: Velouté sauce, creamy soups, chowders
Blonde roux has a slightly nutty aroma and is often used in French sauces.
3. Brown Roux
- Cooking time: 10-15 minutes
- Color: Deep brown
- Best for: Gumbo, Cajun and Creole dishes
Brown roux has a richer, more complex flavor, but it thickens less than white or blonde roux.
4. Dark Roux
- Cooking time: 20-30 minutes
- Color: Dark brown to reddish-brown
- Best for: Authentic Louisiana gumbo, étouffée
Dark roux has a deep, toasty flavor, but because the flour has been cooked longer, it has less thickening power.
How to Make a Perfect Roux
Ingredients:
- 2 tablespoons butter (or other fat)
- 2 tablespoons flour
Instructions:
- Melt the butter in a pan over medium heat.
- Add the flour and stir continuously with a whisk or wooden spoon.
- Cook until you reach the desired color and consistency.
- Gradually add liquid (milk, broth, or stock) while whisking to create a smooth sauce.
Choosing the Right Fat for Roux
While butter is the most common fat used for roux, other options work well too:
- Oil (vegetable, canola, or peanut) – Used in Cajun and Creole cuisine.
- Bacon fat – Adds a smoky depth to gravies and stews.
- Lard – Traditional for Mexican and Southern-style dishes.
If using oil or lard, the cooking time for roux may be slightly longer than when using butter.
Common Mistakes When Making Roux
1. Cooking Over High Heat
Roux should be cooked over medium to medium-low heat to avoid burning. A burnt roux has a bitter taste and will ruin your dish.
2. Not Stirring Constantly
Flour can quickly clump or burn if left unattended. Stirring continuously ensures a smooth, even texture.
3. Adding Liquid Too Fast
Pouring in stock or milk all at once can cause lumps. Instead, add liquid gradually while whisking.
4. Using Cold Liquid
For best results, use warm or hot liquid when combining with roux to create a lump-free sauce.
How Much Roux to Use for Thickening?
The amount of roux needed depends on how thick you want your sauce or soup:
- Thin sauce: 1 tablespoon of roux per cup of liquid
- Medium sauce: 2 tablespoons of roux per cup of liquid
- Thick sauce or gravy: 3-4 tablespoons of roux per cup of liquid
If your dish is too thick, you can add more liquid to adjust the consistency.
Using Roux in Different Recipes
1. Béchamel Sauce (White Sauce)
- White roux + milk
- Used in mac and cheese, lasagna, and soufflés
2. Gumbo
- Dark roux + chicken or seafood stock
- Essential for authentic Louisiana-style gumbo
3. Gravy
- Blonde roux + broth (chicken, beef, or turkey)
- Perfect for serving over mashed potatoes or roasted meats
4. Cheese Sauce
- White roux + milk + cheese
- Used in nacho cheese, queso dip, and mac and cheese
Final Thoughts
Mastering the butter-to-flour ratio for roux is essential for creating smooth, flavorful sauces. The 1:1 ratio is the standard, but adjusting it slightly can change the consistency and texture. By choosing the right type of roux and following proper cooking techniques, you can elevate your soups, sauces, and gravies with ease.
Whether you’re making a creamy béchamel, a rich gumbo, or a simple pan gravy, knowing how to work with roux will make you a more confident cook in the kitchen.