A roux (pronounced: “roo”) is a classic base for sauces, gravies and soups.  It serves as a thickener and is rooted in classical French cuisine as the thickening agent in three of the five Mother Sauces: veloute, bechamel and espagnole.  Unless you’re in culinary school or cooking in a fancy French restaurant, that last sentence probably isn’t something that you will apply to your daily cooking.  However, learning how to make and use a roux is.

First, let’s talk about why you would use a roux.  First and foremost, you would use it to thicken a liquid.  A roux is best used for any liquid that you need to thicken that doesn’t need to be clear.  Think: creamy soups, gravies, cheese sauces, etc.

Secondly, why use a roux to thicken a liquid?  Well, when you need to thicken something, a roux will most likely be your best option because when executed correctly, it ensures your liquid will thicken without lumps and you will end up with a smooth and creamy result.  A  roux is also made out of two ingredients people almost always have on hand: butter (fat) and flour.  Finally, once you understand the basics, it is really easy to execute.

Okay, now that we know the why let’s get into the how of making a roux.  As I said, a roux is a mixture of fat and flour.  The ratio is important here though – it is equal parts, by weight, of fat and flour.  In culinary school, we were trained to use clarified butter in our roux.  Clarified butter is something we always had on hand at school, but not necessarily something every home cook has, so for our purposes, regular unsalted butter works just great.  A note here – you can use any type of fat (oils, bacon grease, etc.) but I prefer butter and flour.

As for for the execution, measure equal parts, by weight, of unsalted butter and all purpose flour.  From experience, I know that 1 tbsp. of unsalted butter and 2 tbsp. of all purpose flour weigh the same and will thicken about 1 cup of liquid to make sauce of “nappe” consistency.  Nappe is a fancy French term which describes a sauce that is thick enough to coat the back of a spoon and when a finger is run through the sauce, the space created by your finger will be remain.  Gravy typically has a nappe consistency.

Now that you have your ingredients, place the butter in a pan over medium heat.  When the butter is melted, add your flour and whisk well.  Continue whisking until the mixture thins and begins to bubble.  Once this happens, cook for another two minutes to get rid of the raw flour taste.  At this point, you have what is called a “white roux”, which is a basic roux that can be used for almost any recipe.  There are many different variations of a roux, the biggest variation being how long it is cooked.  The longer a roux is cooked, the darker it gets and the more nutty flavor it takes on.  A dark roux is especially common in Creole cooking.  If you are thickening a darker liquid and don’t want to lighten it with a light roux, continue whisking and cooking in 2 minute intervals until desired color is reached.

Once you’ve reached the color of the roux you desire, you can add your liquid.  But hold up just a second!  Don’t just go dumping your liquid into the roux.  There are two very specific ways to add your liquid: cold (room temperature) roux to hot liquid or cold (room temperature) liquid to hot roux.  Basically, they can’t be the same temperature or else you run the risk of a lumps.  And nobody likes lumps.  You should also add your liquid gradually, whisking as you go.  Once all the liquid has been added, continue whisking until the roux and the liquid are completely incorporated.  Continue cooking until your mixture is almost at a boil – a roux and liquid mixture won’t thicken until just before a boil.  Once desired consistency is achieved, reduce heat to a simmer and serve immediately.  If your sauce ends up getting too thick, simply add a ladle of liquid and whisk.  Continue adding a ladle of stock and whisking until desired consistency is reached.

This is just an example of how you would use a roux to thicken a liquid.  For my photos, I thickened stock, which is typically the preparation for gravy.  If you needed to thicken a soup, for example, you would most likely be adding a cold roux to the hot soup mix.  If you are not using your roux right away, you can refrigerate until needed. A reminder – a roux is the flour and butter mixture you made.  This post details not only how to make one but also how to use it to thicken something.

So – that’s it!  You just made one of the building blocks on which centuries old French cuisine is built upon.  Pretty cool, eh?

Whisk and cook until the mixture is just about to boil to achieve nappe consistency.

Tagged: butter, flour, French basics, fundamentals, stock