I tried to bake some new potatoes, small tomatoes and hot peppers, in extra-virgin olive oil, using a recipe calling for 1 hour at 100° C.

I was skeptical of the 100° C temperature, so I set the temperature to 120° C instead. However, even after 3 full hours of roasting, the vegetables still had a raw tang, and the texture of the potatoes was a bit rubbery.

What could have been the problem here? Is 120-140° C too low for these vegetables?

(Note: At one point I turned on the ventilation mode, and it seemed to start cooking much faster - maybe even a little too fast. Could the recipe have been intended for a convection oven?)

  • I don't understand what your problem is. Yes, you can cook them at that temperature. Did they turn out wrong?
    – rumtscho
    Jun 1, 2012 at 11:48
  • Yes, mostly they didn't cook as much as described in the recipe, and not in the way described. They still had a raw tang to them. And I kept them in the oven for more than three hours, rather than the hour specified in the recipe. Jun 1, 2012 at 12:00
  • And the texture of the potatoes was a bit rubbery. Jun 1, 2012 at 12:11
  • Cooking time depends on size and shape of whatever you try to cook in a non-linear way. Nobody can predict how long something will take to cook. If you don't want to risk raw food, you should use an oven thermometer. I think that for potatoes, the core temperature you need is about 70°C.
    – rumtscho
    Jun 1, 2012 at 12:19
  • 1
    Welcome to Seasoned Advice. Please try to be more direct with your questions, not to mention concise. In other words, explain in detail what the problem is, and what steps you actually took, and let the people answering handle the explanations and solutions. Also, when referring to a recipe that didn't work out for you, it helps to post either a link to the recipe (if available online) or a summary of it in your question.
    – Aaronut
    Jun 2, 2012 at 16:58

2 Answers 2


Slow roasted vegetables are delicicous. But the accent is upon slow - at 100 degrees you could be talking 6-8 hours. It's very similar ti slow cooked lamb, use lots of olive oil and wait.

I like to put in slices of potatoes for the first three hours and then add pepper courgettes, and other vegetables needing less cooking time for the kast 3 hours.

Great to serve with a half peanut butter, half feta cheese thick dip and some crispy toasted pitta bread.


Potatoes need to reach at least 90C at their center to be cooked. Ovens are notoriously inaccurate. Could it be that, while your oven is set to 100C (or even 120C), the internal temperature of the oven is well below that? I know that my oven is off by 25 to 50 degrees. I have to set it about 50 degrees higher on the dial. I use an oven thermometer to ensure that the temperature is where I want it. My suggestion would be to use an oven thermometer to be certain that you are cooking at the temperature that you think you are.

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