From times to times, I make this soup that consists of 90% onions and 10% green pepper/garlic/white cabbage/carrots. Not matter how much water I add to it, it always ends up quite thick after blending. I own 2 different (Though not particularly priced) hand blenders and normally try to blend the onion stock with both and sieve it, however after blending the soup, there is a thick layer with a paste-like consistency in the sieve that no matter how much I try to scrape using a soup, it just won't strain through. Could I be undercooking the stock?

My method is normally: 1.5kg - 2kg of onions, 1 green pepper, 2 carrots, 1 piece of cabage same weight as carrots. I put it all in the pressure cooker and boil it for about 20 - 40 mins after it peaks pressure in a low heat. On another note, I also notice this puree/stock/soup never really gets very sweet as I would hope it to. Perhaps I need to simmer it longer so as to help the onion and other veg to break?


  • As a basis, are you familiar with the basics of French Onion Soup?
    – Jolenealaska
    Jan 11, 2014 at 6:33
  • Not at all :) I've seen a couple of videos, but this is not really what I'm heading for. Although I mentioned soup, it is just a spicy sauce for indian curries.
    – Goncalo
    Jan 12, 2014 at 0:01

1 Answer 1


For starters, the pasty stuff in your sieve is most likely just fiber from the vegetables. Cabbage and carrots in particular have a lot of fiber and unless you have a really high powered blender, you're not going to break it down enough to pass through a sieve. Most immersion blenders certainly won't be able to do it.

As for the sweetness, usually to bring out the sweetness in vegetables, they are roasted before the liquid is added to make the base of the soup. You could try roasting the carrots and peppers or caramelizing the onions as a prior step.

  • 1
    I would consider the caramelization/roasting step required here.
    – Jolenealaska
    Jan 11, 2014 at 6:29
  • Thank you. I have 2 further questions (1) Would you have any suggestion on which immersion blenders are capable of blending these fibers? and (2) why does roasting cause the veg to go sweet?
    – Goncalo
    Jan 12, 2014 at 0:04
  • 1
    @Goncalo I don't think any immersion blender would do it, unless you removed the vegetables to a smaller container with just enough liquid to help it move. You'd have better luck transferring it to a regular blender. As for the sweetness: sugar caramelizes at a higher temperature than water boils, so in order to get all the caramelized goodness that will dissolve into your broth, you have to cook the vegetables at a higher temperature before adding the water.
    – SourDoh
    Jan 12, 2014 at 4:50
  • Thank you sourd'oh. I can't upvote your comment yet, as my reputation is quite low :)
    – Goncalo
    Jan 12, 2014 at 17:43
  • As an afterthought, now that the time has come to make a new "soup" (gravy), I was wondering whether it would be feasible to caramelise the onions by roasting them along with other veg? If not, would there be any shortcut to caramelise 4kg (8.8lbs) of onions?
    – Goncalo
    Mar 12, 2014 at 1:44

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