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Why Didn't My Onions Carmelize?

I tried and failed to carmelize onions last night. Why didn't they brown? I followed Julia Child's instructions from The Way to Cook, which has you cook them with the lid on for 10 minutes and then add salt and sugar and cook with the lid off. I used a Le Creuset cast iron pot and it was bubbling evenly across the bottom, meaning that I believed the heat was high enough to produce carmelization but not so high that the onions would burn before carmelizing. I kept at it for about an hour and a quarter but then the onions started to break down and I decided I needed to get on with the second phase of the project or we'd never eat dinner. Any suggestions of what I should have done differently?

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  1. Was there a fair amount of liquid in the pot? Did you use any fat (butter) in the process (just curious.) Moisture in the onions that was released when cooking possibly never evaporated so they could carmelize before they started to break down. Could have been the onions you used, perhaps they were very fresh and had a lot of moisture.
    What Julia had you do was to sweat them, covered, then salt, to draw out moisture and sugar, to faciliate the carmelizing step. The salt and sugar also adds flavor. Nothing wrong with this method and besides, I wouldn't dare criticize Julia Child, she's one of my heros. I wouldn't sweat them with the lid on, however but that's just me.
    Yellow onions are best, IMO but people like the sweet varieties, which have lots of sugar, or even reds. Sounds like you got stewed onions, rather than carmelized. The time you spent was significantly longer than it takes to complete the normal carmelization process BUT it depends on the moisture in the onion. Sometimes it can take quite a while for the moisture to evaporate and browing to start.
    If there was a significant amount of liquid in the onions, you can strain out the liquid and continue with the process. If you try this again with the same onions, and find you have a lot of liquid in the pot, try the straining thing.

    5 Replies
    1. re: bushwickgirl

      Yes, I used butter and a bit of oil. I used plain yellow onions, nothing fancy. I bought and cooked them yesterday so they were new to my kitchen but I don't know how long they were in the store. As the cooking process proceeded the liquid definitely reduced and got starchier but they never browned. In fact, at the end of the cooking time the bottom of the pot started to scorch but they still didn't brown.

      1. re: Velda Mae

        You shouldn't have any liquid in the onions to get them to carmelize. A little fat is ok. Maybe you had too much fat. Were you stirring them frequently? If they were starting to scorch on the bottom, they needed to be stirred. Actually, the fact that they started to scorch was an indication that they were going to start to carmelize (the moisture had evaporated) and just needed to be stiired and you needed to turn the heat down a bit to let the carmelizing happen. So you may have been right on the edge of having it work.

        1. re: bushwickgirl

          I doubt it was too much fat; I think the Anthony Bourdain onion soup recipe I made recently called for one and a half sticks of butter, and took time but browned beautifully eventually. I think you're right that the quantity the OP was attempting needed to be turned down, stirred and given time.

          1. re: mcf

            I used 1 1/2 tablespoons of butter and 1 tablespoon of oil for 2 1/2# of onions. I did stir frequently throughout the process.

            1. re: Velda Mae

              I think they needed time, is all, then. My big pot of onions took forever in Le Creuset with all that butter, too. I would've needed a commercial stove and ginormous pan to not have them somewhat deep and crowded before they cooked down. Had to stir a lot.

    2. I agree with bushwickgirl that it sounds like a moisture problem. With a high-sided pot and a LOT of onions, you might have not got the needed evaporation. You tell of the "bubbling" in the pot, which makes me wonder. When I do this process, the sound is really more like a very slight sizzle, and the onions should be good to go in 40-60 minutes max.

      1. You needed a shallower pan with a wide bottom. You had too thick a layer of onions for that style of pot. Also, if you slice crosswise the onions will break down faster than if you slice from pole to pole. If you freeze sliced onions first, they will cook faster than freshly chopped, as long as you break op the frozen clumps. Freezing breaks down the cell walls so the liquid evaporates faster.

        2 Replies
        1. re: greygarious

          Carmelizing onions is not having them break down; that's not the effect you want. Soften considerably and carmelize, yes, but not break down. I define "break down" as fall apart, a problem the OP had and didn't want.
          "Freezing breaks down the cell walls so the liquid evaporates faster." Do you mean that the liquid in the onion will be released faster because they've been frozen and the cell walls have ruptured?
          I agree that possibly the OP may have started with too many onions in the pot but even so they will eventually reach carmelization. I think the OP just didn't cook them long enough.

          1. re: bushwickgirl

            I didn't intend to suggest that the onions need to fall apart - that's why I mentioned slicing them from pole to pole instead of crosswise. Yes, the onion liquid releases and evaporates faster if the sliced onions are frozen - I discovered that serendipitously but of course it makes sense, just like some people make stuffed cabbage by freezing the head rather than boiling it. When I do caramelized onions, it's 5# at a time, and I don't freeze them first, because I rarely have that much free space in the freezer. If I am doing a cooking marathon I sometimes prep too much onion, which is how I wound up freezing a baggie-ful and later discovering how much faster they cooked. I am retired now so am less pressed for time and don't use that shortcut as often. If I have fresh onions around too long and they start to sprout or spoil, I prep and freeze to save the still-good ones.

        2. I disagree with some of the other posters. It simply takes time - a lot of time. Thomas Keller suggests 5 hours of low heat to properly caramelize a lot of onions.

          For instance, in Bouchon, he has a recipe for onion soup... it's basically 1 stick of butter, a dash of salt, 7 quarts of onions and 5 hours of low heat.

          1 Reply
          1. re: tzakiel

            I would think 7 quarts of onions would take 5 hours at low heat, the operative word here being low heat. I've carmelized gallons of onions and yes, it takes time. I don't think any of the posters here suggested otherwise.
            The time it takes to achieve carmelization depends on a number of variables. It's not a thing, as with most cooking, that you can put a number of hours or minutes on, rather, it's done when it's done.

            Without being presumptive, I doubt the OP was cooking 7 quarts of onions.

          2. Agreeing with both grey and tz, to get a true and *even* caramelization, it's the same theory as good bbq - low and slow. This is why I always "go out" when I get a craving of onion soup. I simply don't have the patience to make it from scratch.

            I also agree that the onions need to be, as much as possible, in a single layer across the bottom of the pan. If they're layered up, they will steam rather that brown. Same theory as crowding too much meat/ground beef in a pan to sear.

            To "brown" them (say for spaghetti sauce or chili) still takes mine about 30 minutes on average and even those, I stay just under a medium temp. Even with that, the browning isn't completely even across all of the onions, but since they're not the visual "star" of the dish, I don't really care. (All-Clad stainless)

            1. In my experience caramelizing onions, I find it best to use either a large stainless or large non-stick fry pan. I put a little olive oil at the bottom of the pan, add the onions, stir and just let them fry on a medium to lowish flame without disturbing them too much, maybe stir them every 5-7 minutes so that the moisture has time to evaporate. It takes quite a while for the caramelization to take place but eventually they get there. I've not had much success caramelizing onions in a high sided Le Creuset.

              1. Low 'n slow is my favorite technique.

                Need browned onions in a hurry and it's all about a very high fire, lots of room in the pan and lots of attention.

                1. Jfood normally caramelizings 8# of onions in a 7Qt pot. During the first hour the onions release their liquid, the second hour they begin to release their sugars. Hous 3 and maybe 4, they turn the beautiful brown color and the softness is perfect.

                  So jfood would say you started well but the clock won over the onions.

                  1. Two words--slow cooker. The recipe I use is similar to Bouchon's except I just use three large onions and let them go for about 12-14 hours. I'm still kissing up to the friend who let me know about this.

                    15 Replies
                    1. re: MandalayVA

                      Depends on the slow cooker. I have just a small low/high crockpot, the kind you get for $10 in a drug store. When I tried doing onions in it, on low, they stewed into bland mush without ever caramelizing.

                      1. re: greygarious

                        Mine is a 4.5 quart oval--three onions fill it just about halfway. I tried more once and what happened to you happened to me, a pile of mush.

                        1. re: greygarious

                          I thought one of the main effects of crock pot cooking was lack of water loss? If it works, it's a great idea, but it's hard to imagine, given the high water content of onions and the retention of moisture that crock pots are famous for.

                          1. re: mcf

                            There is liquid but not that much--I strain it out and use it to throw in stews and stuff like that. And it does have to be stirred every so often. I may experiment with stirring more often since that'll bring the heat down and lessen condensation.

                            1. re: MandalayVA

                              I wonder what would happen if the lid were propped open a hair? Do they really get darkly brown with that liquid in there?

                              1. re: mcf

                                Carmelizing onions needs to be done uncovered, so that liquid can evaporate. Slow cookers, while a nice idea for the low temp they maintain, won't work. They need to be covered at all times to preserve the heat level. Opening them frequently increases the cooking time exponentially. Since slow cookers need to be covered, there can be no evaporation, just liquid retention, and your onions will stew.
                                A heavy pan, preferably enameled cast iron or a heavy skillet, is the best bet. This process just takes time, patience, a watchful eye and a stirring hand.

                                1. re: bushwickgirl

                                  Yes, I agree, but the OP says hers caramelized in a slow cooker, despite the presence of trapped moisture, which I found hard to believe, but I'm not about to call her a liar.

                                  I actually know how to brown onions, btw. ;-)

                                  1. re: mcf

                                    My reply wasn't for you actually, I should have replied to the original post, as I was speaking generally. Sorry, Chow can be a little confusing sometimes. Either that or I'm just not paying attention, very long day today.;-00 Upset about Haiti.

                                    The OP cooked hers in a enameled cast iron pot. MandalayVA did the slow cooker. I am with you on the slow cooker thing.

                                    Carmelizing onions is not rocket science, as I'm sure you know.
                                    This process just takes time, patience, a watchful eye and a stirring hand, I'll say it again.
                                    I'm going to go brown some onions now for my peanut butter-veggie stew, which is dinner tonight.

                                    1. re: bushwickgirl

                                      No harm, no foul. If I thought a slow cooker would do it to my satisfaction, I'd go out and get myself a replacement for the one I got rid of.

                                      And yeah, I said OP when I meant MandalayVA. Brain cramp. :-)

                                      1. re: mcf

                                        For those who think onions can't be carmelized in a slow cooker, I present photographic evidence. The first picture is roughly three hours into cooking, the second the end result after about thirteen hours. No photoshopping.

                                        1. re: MandalayVA

                                          Those are stewed, not caramelized. Caramelized onions are very dark brown.
                                          Yours look yellow and a tad soggy to me. Sorry.

                                          1. re: mcf

                                            I admit to not having the greatest camera but they were definitely brown.

                                  2. re: bushwickgirl

                                    Agree; don't get me wrong cause I like Julia but I would think the lid keeps the moisture in the pot which is why it is taking forever to brown....I never caramelize with a lid, and while it takes a good while to properly caramelize onions, I never spend five hours cooking onions..IMO there is no need but to each his own.

                                    And it really does not matter what kind of onion you use: yellow, Vidalia, red, shallots, green onions..I've used them all successfully...

                                    1. re: bushwickgirl

                                      Agree, I don't have time to read all the post but caught yours. Moisture is the biggest problem. Sometimes if there's too much butter, you'll see water come out of the butter and then we get steamed onions.
                                      I like to use a mix of olive oil, and butter. A great deal of onion, like 6 large white onions, and then slice not too thin. Leave them alone, if you start stirring them around, you'll not only break them but you break up that wonderful caramelization that's beginning on the bottom of the pan. So long, slow, and low heat. It just takes a while to get that wonderful color. I've used different pots, and that doesn't seem to matter. I love French Onion soup, and I can tell you, that it does not happen in 20 minutes.

                                      1. re: chef chicklet

                                        Interesting to note that Bourdain's recipe calls for a stick and a half of butter and 8 thinly sliced onions cooked over medium high heat. But his 20 minutes was way off to get the even, dark brown he called for.

                          2. A carmelized onion idea:
                            Carmelize a batch of red onions. When the onions are deeply colored and quite dry, add a splash of pomegranate juice (yes, it will be reddish,) a splash of balsamic vinegar and and heaping spoonful of yellow mustard seed. Season with salt and freshly cracked black pepper. Great for topping burgers, as a filling for mini-tartlets or as a stuffing in phyllo pockets for an appetizer.

                            1. A long time ago I read an article on carmelizing onions which said to slice your onions. Heat some oil or butter over low heat, then add the sliced onions. Stir so all onions are coated.....still on low heat; and then walk away and go about your routine chores. Each time you walk past the stove give the onions a good stir. I use a stainless steel, copper clad pan (Revere Ware), and this method has always worked well for me. Don't use a lid, at all !!

                              Onions generally have a natural sweetness, so no need to add any sugar nor salt.

                              Remove from heat when the proper brown color, cool and refrigerate. I keep carmelized onions on hand in the fridge to add to whatever dish I want them for.....like scrambled eggs (or whatever). I cook a good quantity of onions at a time, and have never had a problem with mushiness. Think the secret lies in amount of onions in pan........very low, even heat, and the patience to allow them develope slowy and gradually!

                              1. Thin feather cut onions?

                                A bit of oil?

                                Low heat?

                                Looooong cooking?

                                No lid?

                                Should be OK.

                                1 Reply
                                1. re: Sam Fujisaka

                                  Why the question marks, birthday boy? Other than jfood likes fatter cuts, those are facts, not items with an A versus B response.

                                  Jfood gonna have some day old cake tonight and sing a big old happy birday to you.

                                  (insert 60 colon-dash-close parens) :-) (that one is for good luck)

                                2. I have spent a lot of time experimenting with caramelized onions because I LOOOVE them. I also have a thing for French onion soup and caramelized onions are critical to that dish. My two cents...when working with 3 lbs of thinly sliced onions I find that they need to hang out in a little sweat lodge (low heat with a lid) with the fat of your choice (I use butter and olive oil) and some salt for at least 30 minutes. This will extract quite a bit of liquid - that's a good thing. Then remove the lid, crank the heat to med-high, and occasionally stir. I also find that deglazing at least twice towards the end really finished things off nicely. It does take time (for 3lbs about 1 1/2 hours), but once the magic/browning begins you will see it all come together. I usually don't see much browning until about 30 minutes after I have cranked up the heat. Just need to be patient. Hope this helps!


                                  Cynthia Brown