Kitchen for Adults: How to Make a Fucking Ru
Roux by any other name is still py, but perhaps that other name should be “thickener of fat and flour paste” because the fancy French name seems to turn people off.
Part of The Grown Up Kitchen series , Skillet is designed to answer your most basic cooking questions and fill in any gaps that may be missing from your home chef education.
The importance of dressing for gravies, sauces, and soups cannot be overstated, but there are an astounding number of home chefs who haven’t even tried it. The good news is that the room is very easy to prepare and we are going to walk you through it slowly and carefully.
First, why do we need these French things at all? Why can’t we just toss a few thickening starch granules into our soup or sauce and let them thicken on their own? According to Harold McGee in his ever-helpful tome on food science, On Food and Cooking , if you add flour or other starch directly to a hot liquid, “it forms clumps and is never evenly distributed: the moment starch granules enter the hot liquid forms a partially gel-like sticky surface that seals the dry granules inside and prevents them from dispersing. ” Cooking the starch in an equal amount of fat before mixing it with the liquid separates the granules, allowing them to gradually get to know their new water friend rather than getting stuck with a harsh injection.
And that’s all that ru – which really means “red”: a mixture of fat and flour that has been cooked a little (or very little, but we’ll come back to that in a minute). When preparing a dressing, you need to pay attention to three main points:
- White: At this point, moisture has dropped out and the dressing is slightly bubbling or frothy, but the color does not change. This takes about three minutes – depending on the fat used – and removes any raw flour flavor. Ru this color has the greatest thickening ability.
- Blond: The flour at this stage takes on a light tan or yellow color and tastes slightly more than the white roux.
- Brown: As the name suggests, this is a ruddy brown wine with a nutty, toasted flavor. This colored Rus is most commonly used in Cajun and Creole cooking and has the least thickening power. Since you want to make sure you are cooking flour and not burning butter, it is best to use butter with a high smoke point over butter.
Measure it
An “equal” amount of fat and flour is needed for a dressing, but not all measurement methods are created equal. Some recipes suggest serving a tablespoon of two ingredients per tablespoon, but if you really want to rock the roux, mass is the way to go.
This does not mean that rus, measured by volume, will not have a thickening power, it just will not have the same thickening power. To understand how excellent the weight measurements are, I made two gravies. The first one I did my usual way. I tore about two tablespoons of butter from the stick, weighed and then measured the same amount of flour by weight (32 grams each, which ended up being about three tablespoons of flour). I then melted the butter in a skillet, added flour, and pushed it continuously with a wooden spatula until I reached the “frothy but still pale” endpoint.
Then I added a cup of duck broth and watched in vague horror as everything clumped together.
Fortunately, with a little vigorous stirring, the flour granules crumbled perfectly and began to work, turning the simple broth into a strong gravy.
Then I add the resulting gravy to the homemade fries , peas, cheese, and a bunch of other crap. It was good.
For comparison, I made another gravy, this time measuring by volume. As you’d expect, the sauce was slightly looser and, as you can see in the photo below, didn’t thicken enough to withstand a full cup of broth.
The moral of the story, my friends, is to measure the mass if you want a delicious sauce.
Color me well
The darker sauce will add more flavor to anything you add, but you need to make sure you are browning the flour and not the oil. If you’re aiming for a good chocolate flavor in your dressing, butter is not the best choice, as these solids will burn and give your sauce a pungent, rather than nutty, flavor. To see how important butter matters, I prepared two different brown sauces with a darker dressing sauce: one with regular butter and the other with ghee. Roux in butter took about 12 minutes to get to this darker, almost milky-chocolate brown place:
The flour cooked in ghee took almost twice as long to turn as dark (the ghee for dressing was also much looser, but this did not affect its ability to thicken):
I then turned each sauce into a gravy, and while they both thickened perfectly, the butter gravy had a burnt and pungent taste, while the ghee gravy had a deep nutty flavor with a large size.
A note on liquids and their temperatures
Many people swear that your liquid – more likely broth or milk – needs to be heated before being added to the dressing sauce. There are those who say the exact opposite, especially when it comes to white dairy sauces such as béchamel.
To be honest, I’ve added milk and broth to dressing at a wide variety of temperatures and never found it to make any difference. (I usually add cold liquids because I’m not worried about the extra step and warming them up ahead of time.) For me, the key to silky and lump-free sauces isn’t the temperature of the liquid. but how well you beat it.
To make a simple cheese sauce, I simply make a white sauce (about 33 grams of fat and flour each) as described above, then pour – I mean plum, not drizzle – a cup of whole milk into the saucepan, whisking continuously. … Of course, there are lumps at first, but over time everything crumbles and turns into a thick, shiny sauce.
After that, I add a handful of cheese, add a little mustard and season with salt and pepper to make a cheese sauce that’s perfect for adding to pasta or pasta.
So, let’s summarize. To prepare rus you need:
- Measure out equal parts by weight of fat and flour, trying to get about 33 grams each for every cup of liquid you want to thicken.
- Cook over medium heat, stirring continuously, until you get the desired color. A white or light color is good for most gravies and sauces, but brown is what you need for most cajun dishes. If you know you will be using brown sauce, use ghee or other oil with a high smoke point. Duck fat and bacon fat are good tasty candidates.
Then you are ready to add the liquid, be it broth, broth, or dairy products. If you’re a little nervous, just add it slowly and stir, stir, stir until the dressing dissolves. Continue stirring until everything is nice and thick, then proudly serve the sauce or gravy.