SNS 007| How to Make and Use a Roux

What Is A Roux?

Roux is a 1:1 mixture of fat and flour that is cooked together and then used to thicken sauces and soups. The amount

Guidelines for Roux

  • Don’t use margarine or shortening. Yes they’re cheap, but margarine tastes horrible and shortening adds no flavor; not to mention it can give you a bit of a fuzzy mouth feel.

  • Use clarified butter, oil or animal fat.

  • When using whole butter for a roux, remember that it's about 15% water by weight, so the roux will need to be cooked slightly longer to achieve the same results.

  • A good roux is paste like and is not runny or pourable. A roux that has too much fat and is too runny is called a slack roux. Excessive fat in your roux will be released into your sauce, making it greasy and forcing you to spend extra time skimming and de-fating.

  • The longer roux is cooked, the more runny it will become and the less thickening power it will have. A general rule of thumb is that a brown roux has 1/3 less thickening power then a white or blond roux.

  • Cake flour has about 20% more thickening power than bread or AP (All Purpose) flour. However, since bread and AP flour are more common than cake flour, most recipes that call for a roux assume that you will be using AP flour.

Making Roux

The process for making roux is extremely simple. Just place equal parts of flour and fat, (traditionally clarified butter), in a sauce pan and cook over medium heat. How long do you cook it for? Well that depends on what kind of roux you wish to make.

There are basically three types of roux which are differentiated by the degree to which they are cooked.

White Roux

White roux is really more of a yellow roux that you basically cook for just a few minutes until the fat and flour are evenly mixed together and start to froth. You want to cook out the raw taste of the flour, but stop cooking the roux before it starts to turn color. White rouxs are used for white sauces that are cream and milk based such as bechamel.

Blond Roux

Blond roux is cooked a little longer than a white roux, just until it starts to slightly turn color. Blond roux is used for white sauces that are stock based, such as veloutes.

Brown Roux

Brown roux is traditionally used for brown sauces, which are sauces based upon brown roasted stocks such as the mother sauce Espagnole. The key to a good brown roux is to cook it over low heat so that it browns evenly without scorching. Some chefs will even dry roast their flour in the oven first before making it into roux.

A good brown roux will have a rich and nutty aroma, and is great for thickening brown sauces and gravies. Just remember that a dark brown roux will have about a third of the thickening power of a blond or white roux.

Incorporating Roux Into a Sauce or Soup

Roux can be added to a sauce either warm or cold, but never hot. A sizzling hot roux will separate and break when it hits a cold sauce, causing lumps and the loss of the roux’s thickening power.

Once the roux is added into the liquid you wish to thicken, whisk vigorously to incorporate and bring sauce to a simmer. Most roux thickened sauces are simmered for at least 20 minutes to cook out any starchy taste created by the flour. During this simmering, it is a perfect time to skim off any scum or fat that rises to the top.

Now what kind of ratio and proportions should you use when thickening with a roux? It’s as easy as 3,4,5 & 6.

  • 3 ounces of roux per quart of liquid will thicken a sauce to a thin or light consistency.

  • 4 ounces of roux per quart = medium body sauce.

  • 5 ounces of roux per quart = thick sauce.

  • 6 ounces of roux per quart = heavy gravy.

Unfortunately, the ratio isn’t quite so easy for my metric friends. If you have any easier way to remember these ratios in metric, leave a comment below, but here is the direct conversion.

  • 85 grams of roux per liter for a thin or light sauce consistency.

  • 113 grams + 1 liter = medium body sauce.

  • 141 grams + 1 liter = thick sauce.

  • 170 grams + 1 liter = heavy gravy.

Site Categories
Video Index: 
Regional Cuisine: 

There are 14 Comments

Porkbutter's picture

When making my roux I'm using equal parts butter & flour by weight, but mine is much dryer than your's is in the video.  While your's seems to be hydrated enough to be able to stir and saute, mine is very pastey.  A one to one ratio is not exactly rocket science, any idea what could be causing the difference? 

jacob burton's picture

My only guess is that you might be using a butter with higher fat content? Whatever it is though, it really isn't that big of a deal. Even though a 1:1 ratio is proper as far as classic cuisine is concerned, I usually just eyeball my roux to get it to the proper consitency and then again eyeball the amount of roux used when I thicken a sauce. I'll add just a little at a time until my sauce reaches the proper consistency.

Not really an exact answer, but I hope this helps anyways. ;-)

Porkbutter's picture

It sounds like it's the consistancy that's important, so I'll just adjust to get the consistancy right and drive on.

Thanks Chef.

CJ's picture

Chef Burton:  What is the technical difference between a sauce and a gravey.  It appears from your overall description that is the thickness but is there a cut-off descriptor that would make one over the other?

jacob burton's picture

Sauces are usually thickened to a consitency that will slightly cover the back of a spoon, commonly referred to as "nape." Gravies are a thicker version of a sauce, generally made from a meat based stock and usually thickened with a roux.

kenash06's picture

This might be a dumb question, but is there a difference between using cornstarch as a thickener for a sauce already containing some fat versus using more and more roux? Or maybe adding some cornstarch to a sauce/ gravy that stared with a roux? 

jacob burton's picture

Cornstarch will do the trick, but it does give the sauce a slightly different consistency and look. Not that there's anything wrong with that, but it will change the characteristics of the sauce slightly. Escoffier himself talked about the virtue of cornstarch as a thickener and predicted that future chefs would make roux with cornstarch and butter instead of flour.

LizAbbott's picture

Hi Chef,


The first roux I ever made was from cornstarch. My dad has celiac disease and as a result he cannot have gravies or sauces made with flour. My mom changed from flour to cornstarch for just that reason. This is how I learned to make my first roux for gravy and it does turn out very good. It gives a very smooth texture with a slightly sweet taste than flour. It is great for those gluten free diets and also in a pinch when your husband forgets to buy the flour at the grocery store even when its on the 


Thank You

Liz Abbott

LizAbbott's picture

Hi Chef,


I make a roux every time I make biscuits and gravy. My roux consists of sausage fat as well as bacon fat to increase the flavor profile. However, I simple take my fat drippings and pour them into a pan and add my equal part part to the fat and make my roux. This part I am good with however, adding the milk is what confuses me. I have always just left my roux in the pot and simply add my milk slowly whisking as I go. I never knew that this is what could cause lumps. I myself have never had a lumpy gravy (except for the lumps of sausage in the Why am I not getting lumps and yet not doing it properly? I have done my gravy this way for years without any lumps, but is it causing other problems I am not aware of? I do constantly whisk my gravy and never let it simmer either. I just whisk until desired thickness and then pour over the biscuits. I just want to do it correctly, so please advise me on this confusion.


Thank You

Liz Abbott

jacob burton's picture

The reason why the gravy isn't giving you problems is because you're making a white or blond roux, which doesn't get hot enough to break. When making a brown roux, the fat and flour become heated way above the boiling point of water, so any liquid added to this extremely hot roux can, but not always, break the roux, causing the sauce to become greasy and lumps to form.



LizAbbott's picture

Hi Chef,


Thank you that clarifies a lot. I am going to try and make a darker roux for dinner tonight and I will be sure to allow it to cool first.


Thank You

Liz Abbott

Graupel's picture

I have a problem that I need some resolution with.
I am making a potatoes au gratin recipe that calls for making a blonde roux and allowing it to cool to room temperature, and then add the blonde roux into a boiling chicken stock (tones chicken base + water), after which heavy cream is added to cut the stock down a bit.  The consistency is sort of a thicker nape that congelates upon refrigeration (this helps to keep the layers of potatoes together and the au gratin potatoes can then be cut into squares and served).
The problem that I am having is this:
Once the consistency is achieved after adding the roux slowly to the boiling stock, I reduce the heat just enough to keep it at a soft boil with a few slow bubbles coming up and then attempt to let the sauce simmer for at least 20 minutes, but the roux seems to separate (break down) in the sauce after about 5-10 minutes, releasing all the fat into the sauce and thickening the center portion of the sauce.  Is there any way around this?  Why is the roux breaking down in my sauce, when supposedly it should be stable enough to allow a sauce to simmer for 20-30 mins?
For the roux I am using Gold Metal All-Purpose Bleached, Enriched Flour and Salted Tillamook butter.  For the proportions of the roux I am using 1 cup butter to 1 heaping cup All-Purpose Flour, whisking until the consistency becomes a slightly runny paste with a buttery sheen.
Please let me know your thoughts on why my roux is breaking down during the simmering process, and if there is any way to avoid it.  I am simmering it at a medium to medium-high heat, just enough to form a few bubbles that rise to the surface.


jacob burton's picture

What you're seeing float to the surface could just be scum coming from the roux, which is always happens. If your roux thickened sauce doesn't thicken, then your roux is breaking, but if the sauce is thick, whatever is floating to the top, is just scum.

If just the middle of your stock is thickening but the rest isn't, try incorporating your roux into your sauce by whisking vigorously.

Hope this helps. If the problem isn't fixed, please send me a picture of your sauce, which will help me to further trouble shoot it.

Let me know if you have any more questions.

YachtMaster11's picture

Thanks for educating me to a highter level of understanding, fantastic site. You asked for a simplification of the "gram of roux per liter" here it is, Base 3 x 3, 4, 5, 6 times 10 let me explain

First of 1 quart is NOT equal to 1 litre it is equal to 9.46353 dl

Second 1 liter = 10 dl. = 100 cl. = 1000 ml. (I know you know)

Jacob you have already done the grunt work by converting the 3, 4, 5 and 6 oz. to gram alas dropping the decimal numbers, in the heat of the battle.

Following your train of thought 3 oz. = 85.05 g. roux to 1 qt. = 9.46353 dl fluid or

9.46353 dl = 85.05 g (3 oz.)

1 dl = 85.05 / 9.46353

10 dl = 85.05 * 10 / 9.46353 = 89.871327084 g or rounded up 90 g per 1 liter

9.46353 dl = 113.40 g (4 oz.)

10 dl = 113.4 * 10 / 9.46353 = 119.828436112 g again round up 120 g per liter

9.46353 dl = 141.75 g (5 oz.)

10 dl = 149.78554514 g rounding up 150 g per liter is there a patten developing here? (30 gram difference between each level) if we add 30 g + 150 g = 180 g and the proof is in the pudding

9.46353 dl = 170.10 g (6 oz.)

1 liter = 179.742654168 g rounding up 180 g per liter bingo!

Rule of thumb: There are 4 levels of thickness, each level increases by 30 g roux, starting at 90 g roux per liter

90 gram roux to 1 liter of liquid will thicken a sauce to a thin or light consistency.

Add 30 g and you have

120 gram roux to 1 liter of liquid will thicken a sauce to a medium body sauce.

150 gram roux to 1 liter of liquid will thicken a sauce to a thick body sauce.

180 gram roux to 1 liter of liquid will thicken a sauce to a heavy gravy sauce.

Back to the beginning, remember base number 3 and 3, 4, 5, 6 times 10 here it is:

3 x 3 = 9 * 10 = 90 g

3 x 4 = 12 * 10 = 120 g

3 x 5 = 15 * 10 = 150 g

3 x 6 = 18 * 10 = 180 g

I am sure you can come up with a smarter solution, sorry for being so long-winded