# Oil/roux temp



## cooknguy (May 19, 2003)

Has anyone measured the temp of the oil/roux while the roux is being made in the skillet? I'm talking about a dark gumbo roux. 

I know the temp will vary, depending on whether med or hi temp is used. Just curious.


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## cape chef (Jul 31, 2000)

?

What are you after?

Are you looking for differnt methodes to make roux?

The temp is important in regards to the time you want to make your roux.

You can do a very slow roux starting with room temp oils/flour, or you can bring your oil to a smoking point and add the flour and do a very fast toast.


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## suzanne (May 26, 2001)

The temperature has to be below the smoke point of the oil being used; otherwise the roux would be incinerated. The temperature will be cooler if it is being stirred constantly than if it is not. A higher temperature may give you a darker roux faster than a lower temperature, but may not develop the flavor as well as a lower temperature over a longer cooking time, and may in fact give you a burnt taste because you will have burnt the flour instead of just cooking it to a deep color. What more do you need, and as Cape Chef asks, why?


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## cooknguy (May 19, 2003)

Thanks for the replies, but I guess I asked the question wrong.

I am an accomplished roux maker. Hi temp, med temp, low temp. And yes, taste changes accordingly. I was just wondering how hot it gets.

Yes, cape chef, I was wondering how companies that make roux commercially do it. I'm sure they have commercial heated mixers.


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## phatch (Mar 29, 2002)

Considering that you can reach the smoke point of the oil with any of the methods, the roux is surely 350-400 degrees when you're in the darker regions of roux.

Phil


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## suzanne (May 26, 2001)

Now that you've got me interested: next time you make a batch of roux, how about sticking a deep-fry thermometer into it for a while, to get an accurate reading? I'd expect that the temperature will be somewhat lower than the smoke point, but by how much?

Big-batch food manufacturers are different from you and me; they have all sorts of fancy equipment that is nothing like what we work with at home or in our restaurant/institutional kitchens. However, they can't heat oil any hotter than we can without burning the roux, if you know what I mean.  They can just do it faster and in greater quantity.


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## pete (Oct 7, 2001)

Not sure exactly how hot a dark roux gets but it gets awfully darn hot, speaking from experience. One of my nastier burns was from a dark roux. The stuff is like napalm!!!It has to be pushing the 350-400 envelope.


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## cooknguy (May 19, 2003)

Well, Suzanne, I thought about that, but since the roux mix isn't but about 3/8 -1/2" deep, I'm not sure how I can get that fat little bulb in there deep enough, without touching the bottom. 

I guess I can do a test, not worrying about the spot at the bulb burning, if I can find a way to clip it.

Now you got me thinking.

Ok, stand back, watch this. :crazy:


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## kylew (Aug 14, 2000)

There is a good reason they call this stuff Cajun Napalm  I saw something the other day that may lessen the need for a near by burn center. The flour was toasted really well before being added to the oil. It certainly shortened the cook time to get a nice dark roux. I wonder if it achieves the same flavor as the trditional method? ANyone ever done this?


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## pete (Oct 7, 2001)

I have known a few chefs that use that technique to make a dark roux (browning the flour in the oven) but I don't feel that you get as deep and rich a flavor as slow cooking a dark roux for 1-2 hours.


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## phatch (Mar 29, 2002)

The technique I use for clam chowder includes an oven baked roux. The roux is whisked smooth at the stove and popped in the oven at 325 for 30 minutes. Comes out perhaps at the dark blonde point of roux. Left it 45 minutes last time as I was set upon by the forces of ****, but it worked out fine, just a bit darker.

That roux was certainly 325ish in temp (assuming oven accuracy).

Phil


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## scott123 (Dec 23, 2003)

Oven baked roux doesn't really work. It's almost impossible to get the same even color to all the flour as you do in a pan. Dry roux can be done successfully in a pan but it's about ten times harder to do well without the oil. Unless you're trying for a low fat dish, use the oil.


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## kylew (Aug 14, 2000)

I am not a low fat cook  I was suggesting that the flour is browned first and then added to the oil.


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## suzanne (May 26, 2001)

Phil's mention of oven-baked roux makes me wonder if it would be possible to make it in a slow cooker. (Forgive me, but I got mine less than a year ago and I'm still playing with its possibilities.  ) It would probably have to be done on the high setting, because you want more heat in order to brown the flour. Hmmmmm -- oil and flour are cheap enough to try, even though I have not plans for its use. Yet. 

As a side issue, does anyone know at what point in the process of making a dark roux the flour loses its properties of gelatinization? All I know is, at some point the roux will no longer thicken liquid; all it provides is flavor. Anybody know the time/temperature? Or will I have to start searching the LSU website?


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## scott123 (Dec 23, 2003)

Even on high, I don't think a slow cooker could hit the temperature (300+) you need for browning.I'm not sure I understand your question. The flour is constantly losing it's properties of gelatinization as it cooks. From the moment your flour hits the hot fat it begins to lose it's thickening properties culminating in complete thickening ability loss when the roux hits black. The ability of a roux to thicken is directly proportional to it's color.


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## suzanne (May 26, 2001)

I was under the impression that, as when cooked with water, flour cooked with fat will also maintain its gelatinization until it has absorbed as much as it can hold. At that point (whether it's in time, temperature, or a combination of the two, I do not know), no more thickening. You're saying it's more of a gradual slide?

Actually, I just now looked it up in _Understanding Baking_ and while I can see that I was wrong -- flour does NOT react with fat as it does with water, and even when it has absorbed all the water it can, it continues to thicken liquid with its burst starch shells -- I still don't have an explanation for the eventual loss of thickening power. Must be because cooking starch in fat affects the cells in such a way as to prevent absorption of liquid when one is added to the other.

But my question remains: at what point does cooking flour in fat prevent its gelatinization? And it is the time, temperature, or the amount of stirring the flour-fat mixture that does it? (Stirring deflates the starch shells.)


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## thebighat (Feb 21, 2001)

Not in my experience. I used to work for a French Canadian chef who had us put about two cups of clarifie in the 20 qt Hobart, then fill it up with flour and paddle it till blended. Then we toasted it in the oven. You have to watch it, and be handy with the spatula to stir it. To use it was just like using cornstarch. Working with him was really an eye-opener as far as making stocks and sauces went. 

Why does this line stick in my head and where is it from.."Under heat, fat percolates through the cell walls of the starch and converts it into dextrin, a substance capable of absorbing six times it's own weight in liquid..."


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## scott123 (Dec 23, 2003)

Yes. Starch + browning temperature = dextrinization = loss of thickening ability

From The University of British Columbia Library Website:

"When flour is heated until brown, the starch granules undergo a process known as dextrinization. Dextrins are fragments of starch molecules composed of chains of glucose molecules. When they are dissolved in water, they have a sweet taste, and contribute to the color and pleasant flavor of brown gravies. As the starch undergoes dextrinization, it loses its thickening power."

Sorry, but when I said "oven baked roux" I meant oven baked DRY roux. Oven baked dry roux doesn't work. I've never baked a fat/flour roux.


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## phatch (Mar 29, 2002)

The roux in clam chowder included fat for its visit to the oven.

Phil


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## cooknguy (May 19, 2003)

Well, I figured it out. Tonight I made several batches of roux with different flours. I checked a couple with the candy therm. It looks like I was working between 350 and 375.


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## pete (Oct 7, 2001)

Suzanne, though I don't know the chemical processes behind why flour loses it's thickening ability, to answer your question, yes, it is a gradual process. As the roux gets darker (aka cooked longer) it starts to lose it's thicken capabilities. That is why gumbo, which uses a deep, dark roux for flavor needs another thickener, in the form of either okra or gumbo file.


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