[mitch]

I am curious as to when to use flour vs. cornstarch as a thickening agent. For example, when I make cream gravy (e.g. sausage gravy), I use flour. What is the practical difference? - Thanks in advance

[Suzanne]

There are a few basic differences:

1. Appearance: flour makes a gravy opaque and can dull or lighten the color, while cornstarch (when used properly) yields a clear, shiny sauce.
2. Flavor: flour needs to be cooked enough to lose its raw flavor; cornstarch doesn't have much flavor on its own. And if you use a cooked flour (such as a long-cooked Cajun-style roux, or roasted flour), you ADD a roasty-toasty flavor you can't get with cornstarch.
3. Cooking time: Flour needs relative long cooking, both to lose its raw flavor and to unleash its thickening powers; cornstarch needs only a short cooking time to thicken. In fact, if you cook cornstarch too long, it lets go and the sauce thins out again.

This is just a start. I'm sure others will chime in with more!

[liv4fud]

I second that suzanne,
Alton Brown did too!

[amorphesis]

does rice flour have the same properties as cornstarch???

[Mezzaluna]

I don't know, but potato starch works similar to corn starch- as does arrowroot.

[Pete]

I also find that cornstarch tends to deaden flavors more than flour does, so you need to make sure your liquid is well seasoned before adding your cornstarch slurry.

[even stephen]

I think the biggest thing a roux has to offer is richness.
I use roux to emulsify or suspend fat into soups or sauces.
with corn or potato starch you lack the richness because
you cannot trap the fat within the liquid. One downside to
roux is the skin that forms on top of the sauce or soup. It
has to be strained constantly. Someone scientific, please
continue with explanations.

[mitch]

Thanks All I appreciate your comments

[shroomgirl]

I use fat with flour....roux with oil or mount with butter/flour.....or pan drippings (aka meat fat).

cornstarch is added more to sauces ala minute for me.....Asian food has more cornstarch.

[MarkV]

Cornstarch however, (and arrowroot for that matter) are more efficient thickeners than flour. Because they are devoid of protein they will thicken with 50-100% greater efficiency than flour.

But of course, all the aforementioned variables must be taken into account when making a final decision of which thickener is best for your specific dish.

Mark

[Suzanne]

I think these questions would be great for our visit by Harold McGee! May I suggest that those of us who have the update of On Food and Cooking check out pages 610 to 620 -- a wealth of information on "Sauces Thickened with Flour and Starch."

[gonefishin]

Hi Mitch,

For a breakfast sausage gravy I like to use flour. But, as others have said...use the flour as a roux. Mixing it with a fat.

For my breakfast sausage gravy I like to brown the sausage in a cast iron skillet...then add the flour (I think three tablespoons or so) and cook, mixing into the sausage. Then add whole milk mixing the entire time with a whisk until the desired thickness is just past (so just a little on the thin side). As the gravy cools down it will thicken up a bit more. Salt and pepper.

dan

[Blade55440]

Don't forget it also comes into play how you're going to STORE said sauce, etc... (if at all). Flour thickened items will hold up to the fridgerator where corn-starch ones will have a tendency to "weep" and lose alot of their thickness while in the fridge.

As for which one to use... depends how quick you need it thickened. If you have the time use a roux, if it's an a la minute kind of thing, hit it with a slurry (I have to say arrowroot is a wonderful thing). As for a sausage gravy... I'd only use flour anyway, but I'm southern and couldn't right call it gravy if I used corn-starch.

[lentil]

So if I understand you all correctly, if I'm going to keep soup warm in a steamer for hours, I should be using flour? When I make a sauce, corn starch would be a better alternative. Thanks for the clarification!

[Ma Facon]

You can make a roux with butter and cornstarch instead of flour, You use less, you don't have to cook it out as long as flour, It is more stable than a butter/flour roux [especially for holding]. The downside is it doesn't brown to different degrees like flour does. Just another option.