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Feb 29, 2012 12:58 PM

Help: making a roux

So I know that fat amount=flour amount, I.e when I'm making a roux I have to use equal amounts of fat and flour. I tried making a roux to make a cheese sauce and completely messed it up. First of all I didn't have any butter so I used lard (its fat, isn't it?) And then when I added in my cornflour (i improvised as i had ran out of plain flour) then added my cheese and it just turned intto a lumpy mess.
My first question is, when making a roux I have to use plain flour amd either butter or oil, no alternatives?
And my second question is how do I know when to use a roux when making a sauce?
And lastly are there any alternatives to making cheesey sauces or is making a roux better?

All help is greatly appricated! And hopefully some day when I understand all the "sciencey" bits of cooking, I can maybe help some one aswell :-)

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  1. You can use lard or any other fat for roux. I would not use corn flour. Use AP.

    If you're making a cheese sauce, do not add the cheese directly to the the roux. Add hot milk and bring to a boil while stirring. Once it boils it will thicken. Then you can add the cheese.

    2 Replies
    1. re: chileheadmike

      What chileheadmike says -

      The roux is just a thickener and binder of a liquid. So you can't just add cheese, you must add a liquid, bring back to a boil to allow the roux to thicken the sauce (it won't reach its full thickening potential until the liquid is back at a boil) and then add your cheese - off heat. If you let it come back to a boil the cheese will likely separate and you will get an oily slick, quite a mess. The flour will actually help prevent this from happening but it can still happen if it gets to hot.

      A roux is just one of many ways to thicken a sauce. Four in general creates an opaque/cloudy sauce and if the sauce is likely to separate (e.g. with cheese where the oil can separate out of the cheese) the flour helps to keep everything together. Flour thickened sauces in general can handle higher heat and don't loose their thickness when reheated. Using flour in a roux (cooking it in fat first) helps to get rid of the raw flour taste and if the roux is allowed to brown adds a nutty flavor.

      You could also use cornstarch to thicken a sauce. Cornstarch typically results in a more clear sauce (e.g. think chinese food sauces) and thickens much more quickly than flour, so doesn't have to necessarily be brought back to a boil. It also contributes very little flavor. It doesn't stand up to reheating quite as well however. So with cornstarch you can dissolve a little in some liquid (e.g. water) and then mix that slurry into your final liquid and voila, thickened sauce. Often used with broths/etc to just give them a little final thickness.

      General rules of thumb between the two.

      1. re: thimes

        Thank you for taking the time to explain about roux and using cornstarch. I'm going to give it a go again and follow every ones advice. Cheers :-)

    2. You can also make a cheese sauce by heating cream and slowly adding grated cheese, stirring all the time. That's how I make it for pasta.

      1 Reply
      1. All of the above. Roux is the oil/flour mixture that is cooked (how long depends on your sauce, from blonde to dark). Then add your liquid, preferable hot, and whisk. Then add cheese to melt.

        8 Replies
        1. re: wyogal

          I added my milk in cold! I didn't do one thing right. So if I'm making cheese sauce, I need to add HOT milk into my roux, then take it of the heat and my cheese sauce!thank you for all tje replies because I get it now. Although out of curiosity say you only had strong white flour or self raising flour, could you use that ? I'm just wondering, becase the day I went to make my roux for a practice, I ended up improvising and using corn starch .. so i was just wondering if u were stuck could you use one of those types of flour?

          1. re: im_with_ana

            not self rising, not sure what strong white flour means..... o.k., just googled it, it's high in gluten. But I would yuse that over self-rsing or cornstarch.
            The milk doesn't have to be super hot, warm will do, be ready to whisk.
            Have fun!

            1. re: im_with_ana

              Self rising wouldn't be the best (you don't need the baking powder) but probably won't a disaster. Strong (or bread) flour should be ok, though a weaker/softer flour is better, since it's the starch that does the thickening, not the gluten.

              Some make a big deal about the temperature of the milk that you add. In my experience it does not matter.

              1. re: im_with_ana

                No, you MUST use a cold liquid into a hot roux if you want to avoid lumping. When you add hot liquid into a hot roux, you get dumplings. You must give the starch granules the opportunity to spread out evenly before they "explode" and gelatinize. The roux and the liquid must always be at opposing temperatures.

                Unless you are an expert sauce-maker and are highly skilled at whisking, using this method gives you much more leeway and less likelihood of lumping.

                1. re: acgold7

                  Yep, you are right. Why have I heard it needed to be hot? or warm? hmmmm (and quite frankly, I thought I was breaking the rules by being to lazy to heat the liquid... hahahaha!)
                  Hot roux, cold liquid
                  cold roux, hot liquid

                  1. re: wyogal

                    One reason experienced chefs use a hot or boiling liquid directly into the hot roux is that it will thicken much, much faster, nearly instantly as the entire sauce explodes into a boil the moment you add the liquid. But you need to be a Robo-whisker to make it do that without clumping up. Amateurs like myself -- I like the greater margin for error with cold liquid.

                2. re: im_with_ana

                  I mistakenly used self rising flour for a dark roux once. It worked, but I wouldn't recommend it. It kept trying to rise while is was browning. It was a lot of fun to watch. I think the leavening eventually cooked out and it came out fine.

                  Don't try this at home kids.

                  1. re: im_with_ana

                    I never use hot liquid. Room temp? Maybe. Cold? Yep, the majority of the time. I think the temp is a personal preference. Adding hot liquid will help it reach a boil quicker but it will also create more lumps.

                    I wouldn't use self rising flour unless it was the only kind I had. I use plain old all purpose flour. Cornstarch shouldn't be used for a roux. It works better as a slurry to thicken after the liquid has been added.

                    Here's a link to a gravy thread here on the board with some helpful tips.


                3. corn flour - are you British? If so, you are probably talking about corn starch (in American usage). That isn't combined with a fat to make a roux, instead it is mixed with a bit of cold liquid to make a slurry, and that is added to the hot liquid.

                  Come to think of it, any other interpretation of corn flour is used as a slurry - whether finely ground cornmeal or masa harina (tortilla flour).

                  Did you add a liquid? or just try to melt cheese directly in the 'roux'?

                  2 Replies
                  1. re: paulj

                    I added in milk and then cheese all at the same temp that had made my (crap/fake/weak attempt of a) roux. So when I'm using corn flour/ starch (I'm irish btw), I need to mix it cold liquid then add it to my hot liquid to create clear sauce? And to make a roux I must use pplain flour and fat! I think I've got it.. I'm going to give it another go asap. Obviously I've messed up from the corn starch right to when I put the cheese in ..

                    1. re: im_with_ana

                      This page
                      and the following one on starch thickeners might help sort out the options

                  2. As far as cheese sauces go, I find that using some cheese like cheddar notoriously don't melt smoothly, can separate and get lumpy, This is the one place where I will use 50/50 Velveeta and cheddar to get the right consistency and some cheddar flavor. Some other cheese sauces like a Mornay sauce which has copious amounts of Parmesan are best used right away and seem to break down the longer you keep it warm on the stove waiting for everything else to cook.

                    2 Replies
                    1. re: LorenM

                      Velveeta and other processed cheeses have emulsifiers that promote smooth melting, and keep the cheese from separating. There is a chow video on how to make your own processed cheese.


                      1. re: LorenM

                        Very right that not all cheese melt the same way into a cheese sauce. So you do have to know a little about how each cheese melts and which work best. A lot has to do with the moisture content of the cheese but there are other variables. A young cheddar for example will melt better than an aged cheddar (which I find also gets grainy). So for mac and cheese for example I use a mix of cheeses.

                        Just to say though - a Mornay sauce is just a classic french sauce that is a bechamel with cheese added. It doesn't have to be parmesan. Even if you add cheddar or velveeta it is technically a mornay (though I'm sure the french would take issue with the velveeta or even calling it cheese but that is a different thread).