A few times now I've been cooking vegetables like butternut squash, sweet potatoes or normal potatoes in the oven and it took ages to get them to soften up.

Usually by the time the recipe says they should be done most pieces are still of the same consistency as when they were raw. Last time (sweet potato, convection 175°C) it took me over an hour to achieve a mostly satisfactory result when the recipe claimed it would take half that time...

So what am I doing wrong? More temperature? More or less stacking? More oil/liquid?

Edit: Yes. Temperature in the recipe and the stove are Celsius. I've cut the sweet potatos into slices of about 0.5-1cm as the recipe called for thick slices. Maybe that's too thick? They were mostly spread out with a bit of overlapping. The recipe taking longer is not a problem in itself but anoying if it's 9 o'clock in the evening and you're still waiting for your dinner...

Update 2: I've retried the recipe last night with the oven at 200 °C the whole time. I've noticed significantly more sizzling after the first phase (20 minutes under the aluminum foil). It took about 20-25 instead of the "official" 15 minutes in phase 2 (without the foil) and was now perfect.

I'm considering a few more changes to the recipe for next time (like extending the steaming time or raising the temp a bit more) but, in essence, raising the temperature did the trick. So I've accepted the answer. Thank you all!

  • 3
    You should get an oven thermometer and confirm the stove is calibrated right. I assume the temperature is in Celsius? Because if the stove is expecting Fahrenheit you are setting it too low. Commented Aug 23, 2017 at 11:05
  • 1
    Recipes usually assume a pre heated oven. Did you do that? And in my experience they sometimes underestimate, and seldom overestimate.
    – user34961
    Commented Aug 23, 2017 at 12:18
  • @Kempeth I see you live in Switzerland, could it be that altitude is extending your cooking times?
    – tkmckenzie
    Commented Aug 23, 2017 at 13:40
  • 1
    175 is a bit low. It depends a bit on exactly how you want them to turn out, but a good start might be to try again at 210+. Generally I think you just found a bad recipe. Try looking at others and see what they say.
    – Niall
    Commented Aug 23, 2017 at 14:26
  • 2
    @Kempeth veg needs a pretty high temperature unless you want to cook it for 90 minutes along with a roast chicken or something. If you want to retain more moisture then cover loosely in tinfoil for the first 2/3 of cooking. Keep the fan on with a minimum of 200, but closer to 220 would be better. In time you can alter things like temperature, cooking time, covering, oil, seasoning etc. to suit different vegetables and your own taste.
    – Niall
    Commented Aug 23, 2017 at 14:48

2 Answers 2


More temperature?

If after an hour they haven't softened up at all, and this occurs with different vegetables (so you're certainly not just encountering a batch of old, dried out gourds or something,) the problem is almost certainly an inaccurate oven thermostat. Oven thermostats are notoriously unreliable. Get an oven thermometer and see what temperature your oven really is.

More or less stacking?

for even cooking and optimal browning, you should arrange your vegetables in one layer on the tray. If this were the primary problem, the vegetables on either the top, bottom, and/or in the middle (depending on the intensity and direction of your heat source) would be undercooked while the more exposed parts would be more cooked.

More oil/liquid?

Note, oil and water based liquids affect cooking very differently. Water-based liquids will get the vegetables to soften more quickly than oil because water transfers heat more efficiently than oil, and it can turn to steam which is a good medium for spreading heat evenly on an uneven surface (such as a pile of chopped vegetables.) It also kills any possibility of browning because water doesn't get hotter than 212. Just because it's in the oven, it doesn't mean you aren't steaming your vegetables rather than roasting them. There's nothing wrong with steamed veg, but that's a very different end-product than roasted veg. More oil will create more crispiness, but a thin, even coating over all of the vegetables should be the only thing you need to roast them properly.

Now, about that recipe: 175 is low for roasting those types of vegetables. Even without par-boiling/steaming them (which lets you finish them at a higher temperature for more even browning and crispiness,) I'd still go with something around 220. That said, even if the cut vegetables were heavily refrigerated, you still shouldn't be waiting hours for them to soften up if your oven was actually 175. Get an oven thermometer!

Good luck, and happy roasting!


For hard starchy veggies like potatoes, sweet potatoes, etc., it's a good idea to first boil them whole to get them fairly soft. Then slice or chop them, and bake them in the oven. Make sure the bottom of the baking sheet is oiled and that you don't layer the vegetables. They should be distributed evenly across the pan in a single layer. Then drizzle oil on top (and seasoning if you prefer). As long as you don't overlook, they should turn out soft on the inside and golden-browned with some crisp on the outside.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.