Twice now, I have burned my onions while heating them in a pan. I was just trying to caramelize them, and they burned every time.

They were on medium heat, and I put olive oil at the bottom of the pan (which may or may not have been a mistake), and they just burned, sticking to the bottom with a fervor I've never seen before (except the other time I tried to heat up onions).

What am I doing wrong?

  • Did you stir once in a while?
    – Mien
    Commented Apr 9, 2012 at 20:22
  • @Mien I stirred a little bit, but I think that was one of my main problems.
    – Emeril
    Commented Apr 9, 2012 at 20:31
  • A heavy frying pan would be a good addition to any of the answers below. Light pans tend to have hot spots which makes this sort of thing very difficult to avoid.
    – vwiggins
    Commented Apr 10, 2012 at 10:41

6 Answers 6


Onions have a lot of sugar in them. All they want in the world is to burn and fill your kitchen with oniony smoke.

The solution, as with all things heavy in sugar, is to turn down the heat and stir frequently.

That said- if your olive oil was extra virgin then it might have been your oil that started burning before the onions did.

  • Hey Soba, I wasn't using extra virgin, but I did heat up the oil before putting the onions in. Also, I didn't stir very much because I was busy screwing up the salsa, but now I will know how to do it next time. Thanks!
    – Emeril
    Commented Apr 9, 2012 at 20:29
  • Olive oil has a low smoking point: always use very low heat (in general, not only for onions).
    – nico
    Commented Apr 9, 2012 at 21:03
  • 4
    @Emeril I hope that you are aware: the medium setting of the stove knob is not always "medium heat". Depending on the material of your pan and how much you fill it, it could produce high heat; it can even turn out that the lowest setting produces medium heat.
    – rumtscho
    Commented Apr 9, 2012 at 21:05

To clarify a little, there are several ways you can cook onions.

  1. You could be trying to get them to turn translucent. In which case, you can cook over medium heat, stirring frequently. This will take somewhere around 5 minutes. Preheating the pan isn't really required (especially if using a non-stick pan). If they start to brown, turn down the heat.

  2. You could be trying to get them to turn translucent, with brown edges. Proceed as with translucent, but make sure to preheat the pan, and also use medium-high heat (but if they get too brown, turn down the heat).

  3. You could be trying to caramelize them, turning them brown throughout. Cook them on low heat. At first, you can stir infrequently, but as they turn translucent and begin to brown, you'll have to speed up your stirring. This takes 30+ minutes.

So, if you were actually caramelizing onions, your heat was much too high.

In general, when something is browning too much (or outright burning) before the center is cooked, you need to turn down the heat or if only the pan-contact parts are browning then stir more frequently. To some extent when cooking in a pan, there is a trade-off you can make: low heat, infrequent stirring, long cooking time vs. high heat, constant stirring, quick cooking.


When cooking it's important to use your eyes, ears and nose.

If the pan is at the correct heat, you can leave the onions alone for minutes at a time, just giving them an occasional stir, but your ears and nose will keep you informed. When caramelising, you should only just be able to hear the sizzling. Anything louder, and they'll probably brown too fast.

If the onions actually stick, the heat is most likely far too high. You need to get familiar with your stove to know what the correct setting is, but even then, remember your ears.


You can also add a little salt to the onions as you cook them. This draws out some of the moisture in the onions and can help stop them browning too much, though not if the heat is very high.

  • Do you have a reference for this claim? My intuition tells me that if you remove the moisture then the food will burn more quickly. Commented Mar 24, 2013 at 14:11

Add a little hot water at the beginning, stir frequently, top up when necessary. When onions at the rigt amount of 'doneness' let any remaining water evaporate and keep an eye on it to make sure the onions don't brown.

  • Welcome to the site, Charles. The OP was asking about caramelizing them. I think your answer does not address that issue, or does it? Commented Mar 24, 2013 at 19:05

1) Olive oil has a really low flash point. Dont cook with it. It will burn at lower temperatures than Canola.

2) you cant just leave them to sit on the pan and expect that t od

  • I don't think it's appropriate to advise cooking without olive oil. Olive oil isn't suitable for high-temperature frying but works very well as the cooking oil of choice for many dishes. Commented Mar 24, 2013 at 14:09

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