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Onions are an excellent addition to many dishes, but cutting them can be frustrating when they make you "cry" all the time.

Does anyone know any tips or tricks to help minimise the tears when chopping onions?

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My secret: wear contacts ;) –  Brendan Long Jul 11 '10 at 5:38
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contacts don't help me in the slightest –  thorncp Jul 17 '10 at 1:07
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My secret: Let someone else cut it for me. Works every time! –  configurator Jul 18 '10 at 23:56
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I'm protecting this question because it already has several excellent answers (including an accepted answer) and we're starting to see a lot of duplicated and/or silly responses. If you have more than 10 reputation and are considering adding your answer, please make sure that it's (a) a real answer and (b) hasn't been submitted already. –  Aaronut Oct 29 '10 at 14:17
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The tears come only after you BLINK. If you get used to keeping your eyes open while cutting onions, it helps a great deal. Other trick is not to expose the the cut side of the onion by putting on the cutting board and holding the onion together. –  MandoMando Dec 3 '10 at 18:46

43 Answers 43

up vote 102 down vote accepted

The tearing of the eyes is a result of enzymes that form a sulpherous gas when the onion is cut (concentrated inside the inner core or bulb of the onion) being released into the surrounding air.

You have a few options to avoid this - one would be to not cut through the center of the onion but to extract the "core". This is kind of a pain and means you are discarding a decent chunk of onion, so I don't like it too much.

Another option is to use a fan to blow the gases away from you. A small fan next to you blowing horizontally should do the trick.

You could also wear goggles, although you'd have to leave them on for a while until the gas dissipates from the area.

Another technique is to cut a lemon in half and rub the fresh lemon against both sides of the blade. You'll have to keep "refreshing" the juice coat and your onions will have some lemon juice on them, so this is somewhat limited by that factor.

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I knew that those safety goggles they made me buy for grade 9 science class would come in handy someday! –  Aaronut Jul 11 '10 at 3:19
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@CodeToGlory: It goes into our eyes. When it combines with the moisture in our eyes it forms a weak solution of sulfuric acid. This stuff burns. :) –  hobodave Jul 17 '10 at 20:19
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There isn't a 'gas in the onion that is released'. There is a compound in the onion which undergoes chemical reactions when cells are burst. This compound is volatile, and irritates the eyes. There is no sulfuric acid. See loc.gov/rr/scitech/mysteries/onion.html –  Adam Shiemke Jul 19 '10 at 16:49
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@Adam Shiemke: Yes, it does undergo a reaction when the cells burst, and true, there's no sulfuric acid, But 'volatile' means that it vaporizes (becomes a gas) easily, so it is indeed released in gas form. It does also contain sulfur. So saying 'a sulfurous gas is released' is pretty much completely accurate. –  Jefromi Aug 16 '10 at 13:46
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@papin: I'd suggest crying is emotional (sorry for the onion) whereas tearing is a chemical reaction. :) –  John K Oct 18 '10 at 4:26

Simply put a teaspoon (steel, of course) in your mouth while you cut the onion. Just try it!

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Just chew gum while cutting it.. You will not cry a bit. It's a master secret.. trust me..

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mentos works as well, just that you need a lot of them –  Jeffrey04 Nov 25 '10 at 13:05

My grandmother had be hold a slice of bread in mouth to form a barrioer between my eyes and the onion fumes.

It worked quite well, and I got to eat the bread afterwards.

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A simple hack is to stick plastic wrap over your eyes. It helps if you have glasses. The poor man's version of goggles.

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My mother suffers terribly when chopping onions. Her solution is to chop them outdoors. It happens that there's a waist-height coal scuttle a couple of paces from the kitchen door, so she does it on that.

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alt text

I was at a cooking class at Sur la Table, and I saw these and thought of your post. Onion Goggles @ Sur la Table

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I couldn't tell you the scientific reason behind this or if it affects the flavor at all (i haven't noticed that is does), but I find that if I freeze an onion before I chop it up, It doesn't make my eyes water.

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Someone showed me this great trick a while back.

  1. Cut a slice off the end of the onion where the scraggly roots are
  2. Soak the onion in a bowl of water for a few minutes.
  3. Chop it normally; discard the water.

You'll see a milky liquid almost squirt out of the onion into the water. The milky liquid seems to contain most of the caustic substance. I think it mellows the taste a bit too.

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Sit down

I simply drag a chair over to the table and sit on it. I cut the onions on the table, but now my face is not directly above it. All the gases go vertically to the ceiling without getting in contact with the eyes.

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Stop breathing the fumes it releases. thats all. Im sure you can do it.

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Use white onions. Yellow onions make me tear up every time, but white onions never do. Go figure.

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When I worked at subway we had to cut all kinds of onions. This is what worked for us:

Wet a paper towel, fold it (hot dog style), and place it under your eyes and over your nose. You have to make sure you don't lean down too much or the towel obviously falls off. Also, it helps to have a large nose.

Then, if we either neglected to do that, or we simply had to cut too many of them, stepping inside the walk in freezer for just 30 seconds kind of re-sets your tears and buys you another 5 minutes or so of tear free cutting.

Obviously most people don't have a walk in freezer, but i imagine sticking your face in a normal one will work equally as well.

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For me, wearing contact lenses works perfectly. I can cut onions as much as I like in them, and never cry. To be detailed, they are AirOptix Night&Day, if someone wonders that some contact lens types maybe don't work.

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Same lenses same effect. No crying during the chopping. I only realize how hard dicing those onions is while I relax my eyes from the lenses and wear glasses. –  Janusz Dec 17 '10 at 16:28

For some reason, I find that onions that have been refrigerated (either in one of those plastic "onion keeper" things, or just in a baggie or whatever) don't make me cry. :)

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Buy the kind of onions that don't make you cry. Seriously. I think several regular onion kinds in US supermarkets (don't know if that's where you are though) are somehow mutated or genetically engineered to reduce the impact. I often eat and cut onions and when I buy this kind, I never cry when cutting it. But I recently bought organic onion and the difference is really noticeable and profound.

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Most 'sweet onions' are lower sulfur, so won't cause you to tear up the same way, but they also won't have the same sharp flavor that the other onions will have. –  Joe May 9 '11 at 17:17

couple of minutes in freezer is just enough, fast and easy...

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Use a gadget that chops it for you.


They can cut it fast and/or keep the gas away from you eg: Tupperware Choppper Gadget

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I man up and just cut it.

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Or if you anthropomorphize the onion. –  Ryan Tenney Oct 29 '10 at 15:20
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I heard Chuck Norris makes the onions cry. –  jontyc Jun 15 '12 at 12:03

Sulfurous gas became sulfuric acid when in contact with water, so with your eyes... simple cut the onion within water and the sulfuric acid will not be volatile, saving your eyes !

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As per Alton Brown:

  • cut near an open flame
  • use a very sharp knife

See Good Eats Moment - Cutting an Onion

As per my father (addendum):

  • make sure the onions are cold
  • hang a piece of bread from your mouth. I've never tried it, but according to him it works. YMMV of course...
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Can't comment directly due to rep limit, but I'm not sure Ryan Elkins above is correct. I'm fairly certain both allinase and LFS are found throughout the layers, though the "core" might contain a higher concentration. Certainly there's no gas contained in the central bulb.

There's a couple of basic strategies for avoiding eye irritation:

Avoid breaking cell walls

The enzymes and amino acids involved in producing the Onion Lachrymatory Factor (seriously!) are normally contained in the cells, and only become a problem when released in volume. Using a sharper knife will avoid mangling cell walls, creating more clean separations between layers, and reducing the amount of enzymes released.

Slow down the reaction

I would guess the activity of both enzymes involved here peaks somewhere around room temperature, or maybe a little higher. You want to get out of this optimum range: either freeze the onion, or heat it beyond denaturation. The former is probably way more practical, since heating to denaturation will leave a soggy mess instead of an onion. You may also be able to deactivate the allinase by substantially altering the pH, for example by coating your knife in lye (not recommended) or lemon juice.

Capture the reaction products

The OLF and the reaction intermediaries look to be fairly water soluble, so cutting under running water should take care of them with sufficient flow rate.

I'm not sure what the mechanism behind the common candle suggestion is, OLF is a thial oxide and not very flammable. My best guess is that the rising air draws some of the irritant up and away from the area, but in that case a fan should work much better.

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Good answer. You get a vote once I can vote again (I'm apparently too much of a vote whore). –  Adam Shiemke Jul 19 '10 at 22:44
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Why does a sharp knife avoid mangling cell walls? I'd expect it to cut right through them! –  configurator Jan 3 '11 at 19:54
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I can attest to the 'Freeze it' method. I have been using it for years now. For me, putting the onion(s) for 10 minutes inside the freezer does magic. –  Ashutosh Jindal Aug 1 '12 at 13:55
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I've heard "have the water running nearby". Any truths to that? Didn't help me, but maybe I did it wrong... –  Slav Apr 25 at 20:34

Wet hands works best for me, just rince your hands under a small stream of water without drying them and start choping.

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America's test kitchen did a segment on this where they tested out a number of different methods including the various folk remedies that people claim works. The only method that they found to reliably work was wearing goggles (you can even buy special goggles specifically made for cutting onions). I don't know if they tested the open flame method or not.

Any method that does not physically prevent the gasses released from the onion from entering your eye simply will not work. The crying is the result of irritation from a chemical reaction when the gasses released by a cut onion interact with your tears (I believe the reaction creates small amounts of sulfuric acid, but don't quote me on that). So you either need a physical barrier around your eyes that keeps the gasses out, or some sort of chemical barrier that will react with the gasses before they reach your eye and therefore prevent them from reacting with your tears.

Of the various answers presented here, the only ones that would seem to have any chance of actually being successful are goggles, a fan (that moves the gasses away from you before they get to your eyes), or possibly an open flame. Of those three, the goggles are the only sure-fire way, as the movement of air is difficult to predict and control.

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As pointed out already by several others the problem is the "gas" that the onions release. You have to try on one hand to crush as little cells as possible (so you use a very sharp knive) and also to prevent the gas from expanding too quickly so you want cold onions (either you put them in the fridge or you put them in cold water before cutting them).

I'm pretty sure the fan trick by Ryan Elkins must work but unless you are cutting onions for a lunch with 50 people that would be an overkill for me :-D

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All I do is peal the brown/whatever skin off, and rinse under water for 10 seconds, then cut however I want.

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Simply breathe only through your nose. Do not talk or open your mouth while chopping. I never cry when chopping onions anymore and haven't in years. I think the bread thing is just a way to keep your mouth closed.

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Yes, this! I agree that the "bread in your mouth" method is really about keeping your mouth shut, as is the "water in your mouth" method. Since I figured this out (not having bread to put in my mouth one day so I just kept it shut) I haven't shed a single onion tear. –  Matthew Frederick Dec 14 '10 at 8:54
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I go for the beer in mouth method. Of course you tend to swallow and then need more. Works for me. –  WW. Aug 19 '13 at 11:42

I know that this may sound silly, but if you pickup a phosphorus match, and bite the base of it (with little red head sticking outside) while you cut onions, you will not cry.

Try it.

Also, after peeling the onion, give it a little quick pass under tap water, before you start cutting it, it helps with not crying.

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I always thought my step-mother was insane for doing this. But it really works like a charm. –  TheHurt May 1 '11 at 23:13

Hold a mouthful of water in your mouth while cutting the onions (don't swallow until you're done). Just try it. I don't know why it works, but I promise it works perfectly.

I'm surprised nobody's suggested this, several generations of my family have used this, I assumed it was a common trick.

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My momma taught me this. Hold a slice of bread in your mouth. The bread absorbs the onion gases. Saliva makes the bread soggy, so chopping a lot of onions requires more than one slice of bread. I've never tried it with spongy white bread.

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