How can I tone down the intensity of raw onion?
Some onions have a more acute taste and smell than others of the same type, and I would like to avoid them in salad dish, or making dips with raw onion. If effectively none, an alternative solution that can also be helpful is to find out what condiments can I add/mix with raw onion to cancel out the intensity of the the acute taste.

There is a uniquely (IMHO) sweet taste to onion that I like. But accompany with that is the acute scene and flavor to it that I wanted to get ride of. I do not want to waste away the taste of onion, but remove the acuteness and remain the sweetness.

  • Just use less? And if you like the texture, add another crunchy/juicy vegetable? (That is, do you actually need to do this?)
    – Cascabel
    Commented Jan 9, 2012 at 5:36
  • 1
    The most effective way to bring out the sweetness and reduce the pungency is to cook them. Is there a reason they need to be raw?
    – Aaronut
    Commented Jan 9, 2012 at 15:47
  • once cooked, they become soft and not crunchy. And I don't want a warm dip.
    – KMC
    Commented Jan 12, 2012 at 7:49
  • @KMC: cold caramelised onions are very good in salads.
    – nico
    Commented Mar 24, 2013 at 21:07

8 Answers 8


Two things control the "sharpness" of onions: variety and age. While certain varieties of onions are sharper than others (i.e. Reds, walla-walls and vidalias are sweeter), any onion which has been in storage too long is going to be sulphurous and sharp-tasting. Since it's January now, that's going to be pretty much all onions.

Since onion sharpness comes from sulphur compounds (as I understand it), the best way to sweeten onions is to release some of them ahead of using the onion. The best way to do that is:

  1. Slice the onion thinly, crossways (parallel to its equator rather than pole-to-pole).

  2. Place the sliced onion in a wide bowl, uncovered or very loosely covered, in the fridge or other cold place for at least an hour and up to a day.

Additionally, either vinegar or salt -- or both -- will help accelerate removing sharpness from onion. For example, for a New Year's Eve appetizer this year I sliced a red onion in to rings, tossed it with 1/2 tsp salt and 2 tsp red wine vinegar, and left it in an open bowl on the 45F porch for 5 hours. The result was intensely sweet red onion which could then be used as a canape topping.

If you're in a hurry, though, the only way to make the onion less sharp is to cook it.

  • 1
    +1 great and useful answer. I always cut it pole-to-pole and didn't realize crossways could helps - does cutting crossways against the pole-to-pole fiber help open up the onion to the air?
    – KMC
    Commented Jan 12, 2012 at 7:57
  • It's also possible to use lemon juice instead of vinegar, depending on the flavour you want.
    – E Jacobs
    Commented Nov 14, 2018 at 16:12
  • KMC: really late response, but yes. You cut onions across the rings/equator to break open as many cells of the onion as possible, and you cut it root-to-stem to break own as few as possible.
    – FuzzyChef
    Commented Nov 15, 2018 at 3:42

Take the appropriate onion for the job. There are sweeter varieties of onions, typically the larger kind (mostly as large as apples), which have widely varying names. This kind of onion has a mellow flavor, and it is what is usually added to raw foods and salads, such as on gyros or so.

  • Yes. Salad onions are marked as such in the shop.
    – slim
    Commented Jan 9, 2012 at 15:19
  • 3
    @slim: That's definitely not universally true. Most places I've seen in the US simply have white, yellow, and red onions. Sometimes there will be sweet onions (which would be good for the OP) but I've never seen anything marked salad here.
    – Cascabel
    Commented Jan 9, 2012 at 22:44
  • 2
    The names are certainly not internationally consistent. In this region of Germany for instance, the mellow onions are called Gemüsezwiebel, which translates to vetegable onion. Elsewhere I heard the normal, pungent kind is also called Gemüsezwiebel.
    – Posipiet
    Commented Jan 10, 2012 at 5:16
  • +1 In my shops nearby onions are just loaded on basket with a simple label "Onions". I will try difference size to see how they can be different.
    – KMC
    Commented Jan 12, 2012 at 7:52
  • If they are in the same basket, they probably are the same type, meaning they will be similarly pungent. The mellow onions are of a different type and should be in their own basket.
    – Posipiet
    Commented Jan 30, 2012 at 1:57

i've read that if you soak the chopped onion in cold water for a bit (5-10 mins) and then drain it well, it will lose much of its intensity.


After chopping the onion, rinse it with cold water and then soak overnight in non-skim milk.


Chop the onion into tiny cubes and plate in a container with a lid. Add a small amount of vinegar and shake the onion until it begs for mercy. When it comes out it will be sweet and retain its flavour. It always works for me.

  • Welcome to the site Mel. What is an onion begging for mercy? LOL Commented Mar 24, 2013 at 19:03

I am a Ph.D. synthetic chemist. I want to share some tricks I have used you might not know about. If you want raw onions that are not sharp soak in either vinegar or lime or lemon juice or salt water prior to use. After burn is removed- can test vs. time- drain off solution before use. The result are onions raw you can use in cooking. OR simple microwave a minute before use does same thing. Professor Marc


One method I've used repeatedly with successful results for red onion, is to chop the onion and let it soak in (white) balsamic vinegar for 10 to 15 minutes. I've never done it with yellow onion, but I imagine that you would achieve similar results.

  • Have you tried this with white vinegar instead? That's a lot cheaper.
    – Cascabel
    Commented Jan 9, 2012 at 22:45
  • I haven't tried it, but my guess is that it would tone down the intensity of the onion, but since white vinegar is more intense, the onion would probably pick up more taste from the vinegar.
    – heyman
    Commented Jan 23, 2012 at 14:24
  • If white vinegar is too intense, just dilute it, rather than using something more expensive.
    – Cascabel
    Commented Jan 3, 2014 at 21:11

I drop them in boiling water for 60 seconds. Reduces some of the bite but keeps some of the crispness. I use for potato salad and add finely chopped celery for a bit of crunch

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