What is it called when you cook butter and flour?
When you cook butter and flour together, it's most commonly known as making a roux. This simple yet fundamental cooking technique is the backbone of countless sauces, soups, stews, and gravies in American cuisine and beyond. It’s where the magic truly begins, transforming basic ingredients into something rich, flavorful, and beautifully thickened.
The Anatomy of a Roux
A roux is essentially a cooked paste made from equal parts fat (usually butter, but sometimes oil or animal drippings) and flour. The cooking process is crucial because it does two main things:
- Cooks out the raw flour taste: Raw flour has a starchy, unpleasant taste. Cooking it with fat removes this taste and makes it palatable.
- Thickens liquids: When flour is heated with fat, the starches in the flour begin to swell and absorb liquid when added, creating a thickening effect.
Types of Roux and Their Uses
The color of the roux is directly related to how long it's cooked, and each color has a different purpose in the kitchen. The longer you cook it, the darker it gets, and the less thickening power it retains, but it gains a richer, nuttier flavor.
- White Roux: This is the shortest cooking time. You cook the butter and flour together just until they are combined and the raw flour smell is gone, usually about 1 to 2 minutes. It should still be pale yellow. White roux is used as a thickener for delicate sauces like béchamel (used in macaroni and cheese, lasagna), cream soups, and gravies where you don't want any added color or strong flavor from the roux itself.
- Blond Roux: Cooked for a few minutes longer than a white roux, until it turns a light golden or straw color. It will have a slightly nutty aroma. Blond roux is used in lighter-colored gravies, velouté sauces, and some chowders where a bit more flavor is desired but a dark color is still to be avoided.
- Brown Roux: This roux is cooked until it reaches a rich, peanut-butter-like color. This takes anywhere from 5 to 15 minutes of cooking, depending on your heat. The flavor becomes more pronounced and nutty. Brown roux is excellent for thickening brown gravies, gumbos, and stews where a deeper, more complex flavor is welcome.
- Dark Brown or Black Roux: The longest cooking time, often 20 minutes or more, until it’s a deep chocolate brown or even black color. This roux has the least thickening power but the most intense, almost smoky, nutty flavor. It's absolutely essential for authentic Cajun and Creole gumbos. Be very careful with dark roux, as it can go from perfectly cooked to burnt very quickly.
How to Make a Roux
Making a roux is straightforward:
- In a heavy-bottomed saucepan over medium heat, melt your fat (typically butter).
- Once the butter is melted and slightly foamy, whisk in the flour.
- Continue to whisk constantly. You’ll see the mixture transform from a clumpy mess into a smooth paste.
- Cook for the desired amount of time, depending on the color you want, whisking continuously to prevent scorching.
- Once it reaches your desired color, you can then gradually whisk in your liquid (stock, milk, water, etc.) to create your sauce or soup base. It's important that your liquid is either cold if your roux is hot, or hot if your roux is cold, to help prevent lumps.
The key to a perfect roux is patience and constant stirring. Don't rush the process, especially when aiming for a darker color, and be mindful of your heat. Burnt roux is bitter and cannot be salvaged.
Beyond the Basics: Variations
While butter and flour is the classic combination, you'll encounter other variations:
- Pan Gravy: Often made by deglazing the pan after cooking meat, incorporating flour, and then whisking in broth.
- Filé Powder: In Cajun and Creole cooking, particularly for gumbo, ground sassafras leaves (filé powder) are used as a thickener, often in conjunction with or instead of a very dark roux.
- Cornstarch Slurry: For a gluten-free option or a quicker thickening method, a cornstarch slurry (cornstarch mixed with cold water) is often used. This is not a roux.
So, the next time you're cooking up a creamy sauce, a hearty stew, or a flavorful gravy, remember the humble yet mighty roux. It’s the secret weapon that elevates everyday dishes into something truly special.
Frequently Asked Questions about Roux
Q: How long does it take to make a roux?
A: The cooking time for a roux varies greatly depending on the desired color. A white roux takes about 1-2 minutes, a blond roux around 5 minutes, a brown roux 5-15 minutes, and a dark brown or black roux can take 20 minutes or more. Constant whisking is essential throughout.
Q: Why do you need to cook out the flour taste?
A: Raw flour has a distinct starchy and unpleasant taste. Cooking the flour with fat (in the roux) dissipates this raw flavor, allowing the ingredients to develop a smoother, more appealing taste profile in the final dish.
Q: Can I use oil instead of butter for a roux?
A: Yes, you can! While butter is traditional and adds a delicious flavor, neutral oils like vegetable or canola oil can also be used. For a richer flavor, you can even use animal fats like bacon grease or chicken drippings, which are common in many traditional recipes.
Q: What is the difference between a roux and a slurry?
A: A roux is made by cooking fat and flour together. It's used as a base for sauces and gravies, providing both thickening and flavor. A slurry is a simpler mixture of a starch (like cornstarch or flour) and cold liquid, whisked together. It's typically added towards the end of cooking to thicken a sauce quickly and is a good gluten-free alternative to a roux.
