Can I Use Less Oil When Roasting Veggies?

I got an interesting comment from a student
in my Orgasmic Vegetables class. Yup, that’s really the name of the class. He said that
he tried roasting butternut squash using my video (that’s before he took a class) and
it never had a nicely browned stage the way the video showed. It was pale for a long time
and then turned black. Any ideas as to what might have caused this problem? I use a lot of oil when I roast veggies. I
mean, at least a ¼ cup for a half sheet and for some vegetables like roasted cabbage wedges
even more. When that student saw me roasting the veggies in class, he was shocked. I use
just as much oil in my videos and I give explicit measurements for them, but I am guessing most
people think they can reduce the oil without compromising the results. I have gotten every
possible reaction in my veggies class when people watch me with the olive oil bottle.
I’ve had jaws dropping. I’ve had people whispering helpful advice to each other along
the lines of “you really don’t need that much oil. I roast my veggies with just 1 tablespoon”.
Look, to each their own. But this got me thinking. What exactly happens when you use less and
less oil? So I set up a little experiment. I cut up a crazy amount of butternut squash
and roasted it with 4 different amounts of oil. Here are the basics of my experimental
set up. For each test, I used 600 grams of squash on a quarter sheet sprinkled with 2.5
grams of salt. The oven temperature was set to 400F which was probably closer to 425F
because my oven runs hot, but it was the same for all the cookie sheets. Each cookie sheet
went into the oven all alone, so that the positioning in the oven was the same. For
600 grams of squash, I normally use 28 grams of oil, so for this experiment, I did it with
7, 14, 21, and 28 grams. As a proper scientific experiment, this was
a complete failure for a few reasons. Every piece on a cookie sheet browns differently.
The center browns the least and the outside browns the most, so doing any fair comparison
of color was very difficult. There was even a difference between the outer pieces. Some
were darker than others. So how would you make sure that you are comparing apples to
apples? I don’t know. It was also hard to show you in the video the textural differences.
It’s not just how dark the pieces are. It’s whether they are developing sticky, caramely
sort of browning or charred sort of browning. Then there was the problem of when to stir
them. Do I stir them when they achieved the kind of browning I like? Or do I stir them
all at the same time. So, after trying this, I realized that I don’t
know how to set up a proper experiment for this to give you good quantitative data, but
it’s hard to spend the entire day roasting squash and not learn something, so here is
what I’ve learned… and keep in mind that this is somewhat subjective. There wasn’t much difference between 21
and 28 grams of oil. Both were delicious and both produced slightly sticky, nicely caramelized
browning. Even 14 grams of oil wasn’t too bad. But more pieces tasted a little burnt
vs caramelized. And with only 7 grams pretty much all browning tasted either wimpy or burnt. A very interesting thing for me was how exactly
do you apply this oil. Normally, I put the veggies on the baking sheet and drizzle them
with oil and toss them right on the sheet. But for this experiment, I used a bowl to
toss the veggies before pouring them onto a baking dish. I think that’s how you are
supposed to do it, but I never do. If you are very generous with oil, it’s not that
hard to distribute it evenly. But the less oil you use, the harder it is to spread it
out over every surface of every piece. And that’s where the bowl comes in. It helps
you give your veggies a good toss. That’s probably why 14 grams of oil was better than
I expected. My problem with the bowl is that I don’t want to wash it and some veggies
like big pieces of cabbage will fall apart if you try to toss them. But there are many
cases where a bowl would help, so if you are reducing the oil in any of my recipes, at
least use a bowl and don’t go lower than 2-3 Tbsp per half sheet. In case you are wondering,
I would use 4. Another thing to keep in mind is that not
all vegetables will react the same way to the reduction of oil because some have more
sugars, some have more water, so there is no one amount that will work for everything.
Because you can’t ruin vegetables with too much oil, but you can easily ruin them with
not enough oil, I just go to town with it. If you want to try my kind of roasted vegetables,
here is how to develop your intuition for how much oil to use. Don’t worry, we are
not going to dirty any measuring spoons or cups or create any extra dishes for you to
wash. Take the cap off your olive oil bottle. Set the bottle on the scale and press the
tare button to get to zero. Pour some oil all over your veggies and put the bottle back
on the scale. Keep doing that until you get to -56 grams for a half sheet. By volume,
that’s a quarter cup and that’s how much oil I’d use. I know most of you think you
don’t need it, but try it once and see if you like the results. Depending on how many
veggies you have on the cookie sheet, and depending on the vegetable type, some of this
oil might not be absorbed after you are done roasting. If that happens, tilt the cookie
sheet for the excess oil to drip out. You could refrigerate this leftover oil and reuse
it. I am sure a question will come up about which
oil I use. I use cheap extra virgin olive oil. The exact brand varies, but at the moment
it’s 365 brand from whole foods. This one is supposedly Spanish. But they sell them
from greece, portugal, italy, etc. I haven’t tried them all. But out of the ones I have
tried, Spanish was my favorite. I don’t like very aggressive or bitter oils. So I
like this one because it’s mild, but you can use anything you want. I tried using non
extra virgin oil for roasting and the veggies had less flavor, so I do prefer extra virgin.
But I also don’t use my finest oil for this. I think it would be a waste of money on a
cooked dish. Save that for your salads or other dishes where the oil won’t be heated. May your oil flow freely and may your vegetables
be delicious. Here are more thought provoking videos for
you to check out and if you are ever in the Boston area, maybe I’ll see you in one of
my classes.


  1. fantastic. now I know I can roast cabbage. Guess what I learnt?

  2. Thanks so much Helen! Definitely need to show this to my mum; she barely sprays her roast veggies with olive oil spray, and then wonders why then never come out the same as when I do them. She never seems to believe me when I tell her that the only difference between when she does them and when I do them is the amount of oil.

  3. Wow such a nice video. Thank you for a scientific approach!

  4. "Orgasmic vegetables class", OMG! 😀
    Talking about oil, I've discovered it by "accident", Bob Ross would say – "a happy little accident" – with the slipped oil bottle: pieces of bell pepper got a heavy amount of oil. The pepper were peeled; I've also used a bowl to season them and cover with oil. After roasting them in the oven, we've put them in a glass container, poured the oil from the baking sheet and decided to even add some of fine olive oil that we normally use for finishing to cover it completely. It were probably the most wonderful roasted bell peppers ever! Few days later we tried to roast some carrots with more oil. They turned out amazing! Our favourite Maldon Sea Salt works like charm here. Of course, there are some exceptions like eggplants, but I would encourage everybody to try this out!

  5. Put veg and oil in a bag, shake bag.

  6. no, you should NEVER eat heated vegetable oils! you get cancer from that guaranteed!

  7. Thank you for that experiment and explanation Helen. I sometimes follow chef AJ to cut down on salt sugar and oil. She sautes in water rather than oil. Never works for me so I use oil in small amounts.

  8. #realcomment No caption.

  9. Thank you Helen. Such a basic topic and yet so important to discuss 🙂 . Also in Indian cooking you will need a certain amount of oil to tempering the spices first and then for sautéing the veggies in the spice infused oil. If you use too little oil neither will it have the rich taste or right texture. And one of the most crucial lessons every Indian grandmother will teach you: When cooking the masala sauce we have to sauté until the oil separates from the sauce again.

  10. Your videos and your approach to topics are excellent. A really underrated channel 👍!

  11. classic students thinking they know more than the people they are paying to teach them

  12. #Comment If you slow roast them too, at a lower temperature, they cook with less oil. You can also cover the pan with foil and let them steam themselves at a lower temp, then take the foil off and raise the temp for the very last part of the cooking and you can get some browning. Your way is better for the roasted flavor, but that's one way to lower the amount of oil. You can just put enough so they don't stick to the bottom of the pan that other way ^_^

  13. Thank you 👌

  14. Orgasmic Vegetables Class, huh?

  15. 400 degress ok how long? and flip when brown say half way??? I just follow you period thank you

  16. I always get looks when I roast veggies just like I will tonight since I'm roasting carrots broccoli and cauliflower.(and garlic) I find broccoli to need more oil then the rest so I toss it separately but people always tell me I'm using to much oil then I'm told the veggies are perfectly cooked.

  17. In the EU we have "Oil extracted solely by mechanical means from whole olives" or words to that effect on the back of some extra virgin olive oils. When I went on a cooking course I was told these are the ones to look for. Supposedly the heat treatment in extraction of oils is what produces the bitterness and so mechanically extracted oils don't suffer from this and honestly I've noticed things do smell better when I use it (but that could just be me). Also blended oils can suffer from separation which can be hard to notice. Luckily in the EU we are spoilt for good quality oils at reasonable prices and they last a good while so just stock up when they're on sale.

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