Flour vs. Cornstarch

Discussion in 'Food & Cooking' started by mitch, Dec 8, 2005.

  1. mitch

    mitch

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    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
     
  2. suzanne

    suzanne

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    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! :D
     
  3. liv4fud

    liv4fud

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    I second that suzanne,
    Alton Brown did too!
     
  4. amorphesis

    amorphesis

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    does rice flour have the same properties as cornstarch???
     
  5. mezzaluna

    mezzaluna

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

    pete Moderator Staff Member

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    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.
     
  7. even stephen

    even stephen

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    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.
     
  8. mitch

    mitch

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    Thanks All I appreciate your comments
     
  9. shroomgirl

    shroomgirl

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    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.
     
  10. markv

    markv

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    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
     
  11. suzanne

    suzanne

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    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."
     
  12. gonefishin

    gonefishin

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    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
     
  13. blade55440

    blade55440

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    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.:)
     
  14. lentil

    lentil

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    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!
     
  15. ma facon

    ma facon

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    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.:chef:
     
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  16. suzanne

    suzanne

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    Right. If you used cornstarch in the soup, as it held in the steamer the gelatinization would eventually break down. With flour, that is less likely to happen -- but then you also have to watch out that the soup doesn't get too thick. If that happens, it's easy enough to add a little stock, scalded milk or cream, or even water to thin it back to the proper consistency.
     
  17. dealinhoz

    dealinhoz

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    Just FYI for those that cook Asian Stirfry, flour is never used as a thickening agent. Stirfries have that dark brown color because of Mushroom Soy Sauce (which is typically thicker in consistency than your standard soy sauce) and if you use flour, it will lighten the color of your dish.
     
  18. frereandre

    frereandre

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    Thank you Suzanne for reminded me to look into McGee...I certainly will...  My interest is finding out which flour works better for a boeuf bourguignon or ragout de boulettes AND being gluten-free. I have been using my own gluten-free flour mix, but noticed that my sauces thinned after refrigeration... which sounds like it is due to the cornstarch content of my mix.  Is potato starch any better? That is a work in progress...lol!
     
  19. boar_d_laze

    boar_d_laze

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    Potato starch is no better.  You're going to have to use more reduction, and other ingredients which add structure -- like tomato paste -- that will help tighten up your liquids rather than binding them.  You can also, when it's appropriate, use things like egg liasons and butter finishes; but they're not germane to your purposes here, and you probably already know about them anyway.  

    Good luck,

    BDL

    PS.  You're lucky to get an answer.  The last response in this thread was six years ago.  Suzanne's post, seven.    
     
  20. chefedb

    chefedb

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    I prefer flour in sausage gravy, and turkey or chicken gravy as it tends to cling better to the product. Cornstarch thickened will run off . Flour based Rouxs must be cooked so the taste of flour is not detected when making a sauce. Hi acid sauces will break down starch thickened sauces when cooked over long periods.  Starch yields a clear sauce where flour does not. I have worked in classical kitchens where cornstarch is not permitted but is in the pastry shop it is. Both are good and acceptable when used in the proper way.