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Mac n Cheese -- Why does my sauce separate?

I've tried various mac n cheese recipes and always my sauce separates and seems oily. WHY?? What's your favorite recipe?

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  1. Assuming you're making a bechamel sauce: it's probably the cheese melting at too high a temperature. Some cheeses (like cheddar) tend to separate and get oily/grainy. Here's a couple hints:

    1) Use a mix of cheeses, including some that melt more smoothly. My faves include asiago, fontina, gruyere, or even gouda (for a bit of a different mac n cheese flavor). I like the sharp cheddar taste, but using more than about 1/2 cheddar risks separating and graininess.

    2) Add the cheddar last, and only after you've turned off the heat. Stir well until melted and mix into the pasta...

    Good luck!

    1 Reply
    1. re: another_adam

      Don't forget blu cheese :)

      Adam is right on this one- the big thing is whisking in the cheese after you remove from the heat. The way I do it is to put my large sauce pan on my cutting board and slowly whisk in the cheese, not adding more until the first bunch is melted.

      Last recipe I used I went with 3 cups of shredded cheddar (a combination of smoked cheddar and extra sharp) to 1.5 cups of crumbled blu cheese.

    2. are you binding the sauce with a roux (flour and butter) or cornstarch? you need something to hold the milk and cheese together. if not, you could heavily reduce heavy cream (till it thickly coats the back of a spoon) and add the cheese. using cream cheese will help bind it as well.

      1. melt butter, add flour (equal parts each), wisk to form the roux. cook for 2 minutes on medium.
      2. add milk slowly, wisking to prevent lumps. let it come to a boil and simmer for 10 minutes.
      3. add desired cheese (i use cheddar, parmesan, and cream cheese.) you can remove the pan off the heat when you add the cheese.

      9 Replies
      1. re: Antonio Montana

        oh yes, a little cream cheese also adds a kind of sinfully rich creaminess to the bechamel (asiago has a similar, but "cheesier" effect)

        what kind of parmesan do you use? i would have thought it would separate or get stringy, too...

        1. re: another_adam

          Cream cheese? I've never thought of that... very interesting. I'll definitely have to experiment with it.

          To the OP, as others have said, if you are doing pure cheddar and nothing to bind it (roux, stabilizer, etc.) then you'll always get some separation. With something like a gruyere, you can get away with it, but a mix is best. I actually like 2/3 sharp cheddar and 1/3 monterey jack. A bechamel works well to bring it all together in the right consistency. However, I'm not a huge fan of a bechamel flavor in mac and cheese. I've started experimenting with gums, like guar gum, as a stabilizer for cheese sauces.

          1. re: adamclyde

            Wow, this does indeed sound like a project for food scientists (we need a "Cornell Mac 'n Cheese"!)

            I've always wondered about applying some fondue-stabilizing techniques. Swiss acquaintances have told me that a little creme fraiche helps (maybe similar to cream cheese?) And laying out the grated cheese to dry for at least an hour or two before melting.

            One other suggestion for the OP: are you using a recipe with egg? If so, you need to be sure to bake at a lowish temperature, maybe even in a water bath, so it all cooks gently and evenly without "breaking"

            1. re: another_adam

              I just like your posting name. :)

              I've never thought of using creme fraiche in mac and cheese, though I can see how that works. It certainly works well in cream or milk-based pan sauces, as creme fraiche withstands heat quite well.

              1. re: adamclyde

                An easy recipe for creme fraiche is to mix at room temperature a cup of heavy creame with either 1/2 cup sour creme or 1 T buttermilk, also at room temperature. Cover and shake for 15 seconds. Leave stand at room temperature for 24 hours, mixing occasionally. This can be refridgerated for 2-3 weeks.

            2. re: adamclyde

              Alright Adam, breaking out the guar! :)

              How do you like it so far?

              If you want to take it to the next level, combine guar with xanthan. They have a phenomenal synergy with each other.

              Bechamel does tend to give cheese sauce a bit of a bready/cerealy note. Are you looking to bypass the bechamel completely? If this is your goal, I'd recommend combining the gums with arrowroot. Arrowroot lends a much cleaner taste to cheese sauce than flour does, and, by sharing the load, you won't overdo the gums/create sliminess. The other nice thing about an arrowroot/gum sauce is the time saved from not having to make a roux. Just sprinkle/whisk the gums and use a slurry for the arrowroot.

              The one tip I'd recommend for working with guar is to get it into the milk/cream right off the bat- first thing. I find that no matter how carefully you incorporate gums, there's almost always a little clumping. Heat helps break down the clumps, to an extent, but time is invaluable. The longer the gums have contact with the liquid, the better.

              1. re: scott123

                been using it in different applications, on your encouragement, thanks very much, btw.

                Like it so far. Mostly been in ice cream, but started a few weeks ago experimenting with cheese sauces too, since I've never liked flour thickened cheese sauces for some reason. They just taste flour-y to me.

                If I could find Xanthum in smaller quantities, I'd grab some, but so far, I can only find it in gigantic bottles... I'll keep looking though.

                1. re: adamclyde

                  You're welcome.

                  It is kind of ridiculous the amounts of xanthan they sell. With the xanthan I got from Whole Foods, it's probably enough to last 3 lifetimes and I use it just about every other day. As far as I know, it keeps forever in an airtight container (I use a glass PB jar), though, so I'm not worried about it going bad.

                  If you've got an issue with the flour-y taste of bechamel, I have two suggestions.

                  1. Take the roux to a slightly darker shade. Instead of a 1 minute-ish white roux, try a blonde roux, or maybe even slightly beyond that. Think liquid shortbread. As you toast the flour, it gets a nutty character and the taste changes dramatically. Just make sure the heat is low so the flour toasts evenly.

                  2. Simmer the bechamel for 10 minutes... maybe even 15. Simmering a flour based sauce goes a very long way in breaking down the starch granules and removing the floury taste. Gravy is complemented by extended simmering as well.

            3. re: another_adam

              I'm not sure of the chemistry involved, but I have found cream cheese to be exceptionally UNstable in cheese sauce. I've had more cream cheese sauces curdle on me than any other type of cheese.

              The other thing that I noticed about cream cheese based sauces is that they store poorly. If, by babying the heck out of it, I am lucky enough for the sauce not to curdle, if I then refrigerate it overnight, it's toast.

              My handful of experiments with cream cheese have been at fairly high concentrations. Maybe if you use just a little, it might be alright.

              From my experience, though, I definitely view cream cheese as a de-stabilizing force.

          2. Are you thoroughly draining the pasta after boiling? Those macaroni tubes can hold a lot of water.

            1. I have used this recipe over the years with much success. I saute a few tablespoons of finely chopped onion in butter first before adding the flour to make the roux, but otherwise stick to the recipe. I have made it with parmesan and cheddar as called for, but also have used other cheeses when I needed to clean out the refrigerator -- if it shreds, grates or crumbles I'll use it. In addition to making the roux properly, the parmesan helps to keep the cheddar from separating. I always use some amount of good quality extra sharp cheddar in addition to other cheeses and have never had a separation problem. http://www.epicurious.com/recipes/rec...

              1. I love mac and cheese and I love all the variations, actually you can switch it around with the cheeses. If I don't make a bechemel sauce first, the cheeses just don't adhere to the pasta like it does with a base sauce first. One of the best recipes I've tried is to make your bechemel, add your cheeses, pour it over the pasta into a casserole and then taken a beaten egg and mix it in with the pasta. cover with extra cheese, and lots of bread crumbs, bake at 350 until bubbly then brown the top if it isn't under the lowest setting under the broiler. I believe this might be more southern style mac and cheese. But served with fresh cold tomatoes, and hot sauce it is terrific! Left over mac and cheese can then be made into balls to fry.
                Well, I never said it was low cal.....

                1. Here are some traditional ways to help prevent curdling:

                  1. Once it's fully thickened simmer your bechamel for 5 to 10 minutes. Too long and the milk starts getting a cooked taste, but too short and the starch particles don't absorb enough liquid/swell.
                  2. Before adding the cheese, whisk the bechamel aggressively. Whisking helps break down the swollen starch particles, which, in turn, helps to create both a smoother and a more stable sauce.
                  3. Add the shredded cheese off the heat The residual heat of the bechamel should be sufficient to slowly melt the cheese. If additional heat is necessary, put the sauce back on very low heat, very briefly. Never let your sauce come anywhere near a boil.
                  4. Additional fat - fat (in the form of whole milk/cream) is a powerful stabilizer. Be careful with the cream, though- too much and it starts to mask the taste of the cheese. 2 parts milk to 1 part cream is about as high as you want to go.
                  5. Use fresh milk - old milk curdles more easily than fresh milk.
                  6. Use younger, less sharp, less aged cheeses - acid curdles milk. Older cheeses have a higher acid content. Until you've mastered stable cheese sauces, stick to mild cheddar and colby.
                  7. Use sealed cheese - opened cheese has a tendency to dry out and be harder to melt
                  8. Watch the salt content of your cheeses - salt can be a destabilizing factor. Blue cheese is especially salty. If you do add blue cheese, make sure to compensate by adding more cream.
                  9. Add a small amount of American cheese - it contains chemicals that prevent it from curdling. Kraft Deli Deluxe is better than most.
                  10. Don't make your cheese sauce in advance. A borderline stable cheese sauce, when refrigerated overnight, will usually curdle.

                  Some less traditional ways of preventing curdling involve:

                  11. Hydrocolloid gums - xanthan, guar (these are especially useful for providing stability but not masking flavor like starch/cream does). If you use too much the sauce can get slimy, but in very small amounts they work beautifully.
                  12. Mustard - mustard contains emulsifiers which help stabilize sauce, but... I don't think it brings that much stabilization to the table nor is the taste favored by everyone. I'm not a big fan.
                  13. Milk proteins - dried milk/whey is sometimes used commercially in cheese sauces, but, like mustard, I'm not a big fan of the taste.

                  For an unbaked mac & cheese, following tips 1-10 will pretty much guarantee you a smooth, uncurdled sauce. Baking exposes cheese sauce to pretty extreme temps and pushes the stabilization envelope. The starch from the unrinsed pasta helps a bit, but not much. For a guaranteed not to curdle, baked mac & cheese, I'd incorporate a gum (or two) into the mix. Whole Foods carries xanthan.

                  Can you ignore all these recommendations and still make an uncurdled cheese sauce? Of course. Each of these tips, though, improves your odds. Curdled cheese sauces are the worst. Anything you can do to help prevent curdling is well worth the effort, imo.

                  1. I first melt my 4 tbl butter and then whisk in 1/4 flour until smooth, all under low heat for a few minutes. I add 4 cups milk slowly while whisking. Whisk until boil, thicken and lower heat and cook for 10 minutes or so. Season with spices.

                    In a seperate bowl, compbine 3 or so cups of cheese with milk and and combine, pour over noodles and more cheese to top , 1 cup or so.

                    I have also added cream cheese to this and marscapone in addition to the shreaded cheese.

                    Bake for 45 minutes and serve.

                    Some people also add prepared mustard to give it a tang.

                    I like using parmasian and sharp chedder, my kids like mild chedder.

                    1. y'all are too fancy - you don't need roux, eggs etc.

                      you need velveeta.

                      ;) :) :)

                      4 Replies
                      1. re: hitachino


                        its funny. as a little kid, I used to love this dip my mom made that was two ingredients. velveeta and canned chili. For some nostalgic reason a while ago, I decided to go against all culinary intelligence and try it again. It was like eating melted plastic. man that stuff is nasty. Who cares if it melts smooth if it tastes like crap.

                        the sad thing is, I think my mom still makes that dip and makes mac and cheese with it. yikes. My influence on her is pretty limited, obviously.

                        1. re: adamclyde

                          well, i was joking (sort of):) - isn't adding a bit of velveeta just like adding regular american cheese? (as others here have already suggested)

                          years ago as a barmaid, we had a happy hour nachos deal -- made in a crock pot. velveeta and salsa and store bought chips. people couldn't get enough. (ok, so they were pretty 'happy')

                          maybe kraft has changed their velveeta recipe since the good ole days.....(just like they've messed with their hellman's mayo recipe)

                          1. re: hitachino

                            Hitachino, I was the one who recommended adding 'a small amount' of American cheese. Velveeta tends to be a little bit saltier than American, but if you use a small amount of it, sure, I think that could work, but the operative word is definitely 'small.' For 3 ounces of cheddar, I use about 1/2 ounce American.

                            Adam's use of the term 'melted plastic' to describe high quantity processed cheese sauces is right on the money. I've been lazy a couple of times and attempted to make a sauce with just American cheese. Not good.

                        2. re: hitachino

                          Growing up my mom would make mac and cheese for we kids, and we LOVED it. I still think it makes a great grilled cheese too!

                        3. Try using a can of evaporated milk , rather than fresh. It's designed to be stable at high temperatures, and is perfect for mac & cheese. However note that each can is 400 calories, so be careful in going crazy with this stuff!

                          1 Reply
                          1. re: AKR

                            A famous not-to-be-named magazine/cooking show recommends this as well. Here's a paraphrase of the recipe:

                            Creamy Macaroni and Cheese

                            Bread Crumbs:
                            1 cup fresh breadcrumbs from French or Italian bread
                            Pinch table salt
                            1 1/2 tablespoons unsalted butter , melted

                            Pasta Base:
                            2 large eggs
                            1 (12-ounce) can evaporated milk
                            1/4 teaspoon hot pepper sauce
                            2 teaspoons table salt
                            1/4 teaspoon ground black pepper
                            1 teaspoon dry mustard , dissolved in 1 teaspoon water
                            1/2 pound elbow macaroni
                            4 tablespoons unsalted butter
                            12 ounces sharp cheddar cheese , American cheese, or Monterey Jack cheese, grated (about 3 cups)

                            1. Toast bread crumb ingredients on a cookie sheet at 350F.
                            2. Mix 1. c. of the evap. milk, eggs, hot sauce, 1/2 tsp. salt, pepper, and mustard in a small bowl.
                            3. Boil macaroni in salted water until almost tender. Drain. Toss with butter.
                            4. Pour egg mixture and 3/4 of cheese over noodles. Stir. Add additional evaporated milk and cheese and stir until creamy.
                            5. Top with breadcrumbs and serve. You can also top with breadcrumbs and briefly brown under the broiler.

                          2. This all sounds good except even though I love blue cheese in salad, I don't like it in a cheese sauce.

                            Note that the key in almost all of the above suggestions is grating the cheese.

                            If you have some Laughing Cow Swiss around I've found that adding just one little triangle (3/4 of an ounce I think) to a cheese sauce really smooths it out.

                            My mother used to make mac and cheese differently from what's being described here. She'd make a bechamel and then mix that with the cooked mac and then stir in tiny cubes of cheddar before she baked it. When I was little I loved the contrast between the macaroni and the little melted cheese bits.

                            1. Oh, one more thing that I just remembered. I'm not 100% certain about this, but I believe thick sauces tend to be more stable than thin. In other words, if you're having stabilization issues, you might want to try making the bechamel with half the milk, melting the cheese, and, once the cheese is completely melted, adding in the rest of the milk.

                              1. Thanks everybody, I think I finally made a mac n cheese I can be proud of. I think my biggest mistake before was putting in sauteed onions -- that's what made it greasy. Tonight, I tried Ina Garten's recipe again and took it off the heat before adding cheeses. Also added 1/2 a large pkg of cream cheese, in chunks, as some of you suggested. I baked it in my new red Mario Batali lasagna pan from Crate & Barrel. Wish I knew how to put on a photo of it. Only problem now, too many dishes to wash. People who've never made this don't know how much work, dirty dishes this entails!!! Thanks again!!

                                1 Reply
                                1. re: walker

                                  Really? Sauce pan, pot to make pasta in and baking pan? 3 I count. Maybe 4 if you count your measuring cup.

                                2. resurrecting an old thread...i followed the epicurious recipe to a tee and my sauce still curdled. the only change i made was using lactose free whole milk. could the lactose free thing have anything to do with the curdling??

                                  4 Replies
                                  1. re: trolley

                                    Hmmm... I can't say for certain, but I don't think lactase should impact cheese sauce stability. I found a few mac & cheese recipes on epicurious. Could you post a link?

                                    1. re: trolley

                                      I don't know the chemistry, but if the lactose-free milk was your only deviation from what others find to be a successful recipe, then it's a logical conclusion that the milk was to blame. I am very lackadaisical about mac&cheese - I make it when I have cheese and milk (or half&half, or light cream) that is close to turning sour and needs using up. I always use evaporated milk, which means a roux is unnecessary. Always dried minced onion and prepared mustard. I often buy cheese deli ends, which give me some American cheese to include in the mixture, or occasionally some Velveeta. Even though I just melt hunks of cheese in the milk, over low heat, it all ends up being smoothe.

                                      1. re: trolley

                                        could the lactose free thing have anything to do with the curdling??
                                        it shouldn't. i used to use it to make béchamel & various cheese sauces all the time and never had a problem with it breaking or curdling. flavor, however, is an entirely different issue - lactose-free milk is just to darned sweet for me! ;)

                                        assuming you used the 1994 Gourmet recipe Ellen linked to above, i have to wonder if perhaps you just had the heat too high when you cooked the béchamel, because i can't imagine what else would have caused it to happen. did it break before or after you combined it with everything else & baked it?

                                        1. re: goodhealthgourmet

                                          thanks for your insight into the lactose free milk. yes, it's way too sweet for my likings as well but it's all we get in our house so i'll take it. yes, the link above is the recipe i manage to destroy.

                                          i DO think i heated the béchamel too high. i also think the pot was too hot. what i did was drain the macaroni then put them back into pot i boiled them in and poured the sauce over it and put the lid on it. i went back to it about 10 minutes later and it was all curdled. i think the pot was way too hot and i feel like the sauce was already sort of curdled when i poured it.

                                          i'm going to attempt it again b/c the sauce i attempted to make with just cheese and milk was even a bigger disaster. they never mixed together as promised and it was a big mess.

                                          once i stop feeling sorry for myself i'm going to take another shot at the mac and cheese!

                                      2. Ditto on the extra fat. Beard recommends 1/2 cup creme fraiche to the bechamel. That's what I do and I can still used aged Vermont cheddar that simply can not be beat.

                                        Another way to do is to use the quatro formaggi technique. Have the casserole hot, toss hot pasta in a cup of heated, reduced cream, add the cheese and cook at 500 for a few minutes.

                                        The reduced cream version of veloute is another option though I haven't tried it with aged cheddar.

                                        1. I used to have this problem, my sauce would break in the oven.

                                          I no longer make a "cheese sauce". I use fontina and a soft cows milk cheese with peppercorns that I can never remember the name of, mix all ingredients in a covered casserole dish and bake for about 20 mins. Stir.

                                          I usually use a lb of pasta
                                          about a lb of cheese (1/2 lb of each)
                                          Pancetta or guanciale
                                          a bit of cream

                                          1 Reply
                                          1. re: Sharoneonta

                                            i've been struggling with this b/c i don't want to waste another good block of cheese and waste my time again. so today when i was at whole foods i asked one of the cooks how they make their mac and cheese at the hot bar. i like their mac and cheese and i'm always amazed at how it stays together without curdling while sitting in those hot containers( i have no idea what they're called) anyway, she said they dump the cheese (which has to be a combo but always has mozzarella and cheddar) in a pot and add some water and melt it. they also add in some milk and that's it! so sharoneonta, i'm going to try your method tomorrow.

                                          2. My husband makes the mac and cheese in our house. He starts with a Le Creuset shallow casserole over medium heat, warms heavy cream and then slowly adds in cheese--usually parmesan, comte, aged cheddar and some roquefort or stilton. Once it is all looking yummy, he adds in cooked shells, stirs it all around and then bakes for about 10 minutes at 450 or so until it is brown on top. Never had it separate, never had anything but a scraped clean Le Creuset dish at the end. Truly, why do a roux except to save a few calories?

                                            1. I really hate to say this because Hounds will start barking
                                              and braying that FoodFuser has strayed from True Cheese.

                                              Gollop it up with Gruyere, Swiss, or Cheddar,
                                              and melt it into your best bechamel.

                                              While this is tradition
                                              another rendition
                                              may help with that break of the sauce.

                                              There is good simple chemistry
                                              behind the utility
                                              of adding just a bit of Processed Cheese.

                                              It's Sodium Citrate spreads through your matrix
                                              and yields your desired emulsion.

                                              The easiest one to use is labeled "American".