How can I chop onions without crying?

Question

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?

Answer 1

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.

Answer 2

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.

Answer 3

The best thing to do is very simple: use a very sharp knife and cut them quickly. This causes a minimal amount of the gases in the onions to be released.

As for "tricks", I find that placing a candle by the cutting board to burn off some of the gases released helps for me.

Answer 4

Stick it in the freezer for half an hour first. I just discovered this by accident (I went to get bacon out of the freezer and absent-mindedly put the onion I was holding in the freezer at the same time!)

Answer 5

I man up and just cut it.

Answer 6

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...

Answer 7

I chop them in half, then run them under the tap, then finish them off.

This seems to get rid of most of the crying-chemical for long enough for me to finish anyway.

Answer 8

Dicing onions is the act that takes the most time and cutting and so it likely to cause the most tearing. Here is my technique, and I can dice literally 15 onions before my eyes start to tear up.

1. Cut the onion in half, laying the cut sides down. This will keep the gases from escaping while you gut the first half.

2. Slice long longitudinal cuts, leaving the slices attached near he root.

3. Finish your dice with lateral cuts.

4. Put the diced onions in a bowl about 2 feet away.

The trick here is to leave the second half cut side down while you work with the first half. It makes all the difference.

Answer 9

Cutting them underwater is a little difficult but is the best technique I have tried

Answer 10

Here is an article that lists quite a few interesting ways to avoid it. One I think is worth mentioning is to cut the onions under water. I've also read that putting the onions in water for 30 minutes before cutting also helps. Both of these methods would help reduce the compounds that are released when chopping and stop them from going after your eyes :)

Answer 11

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.

Answer 12

Learn to cut onions faster. Seriously. Unless you're working in a restaurant kitchen and will have to chop more than a dozen (or hundred) of onions, you should be able to chop it fast enough and store them or cook them right away. Then take a few steps back until the gas dissipates from the cutting area.

If I have several to do, I peel them all and cut them in half. Then I do all the chopping at once. You don't need to be a knife master. Just good enough and have a good knife.

Answer 13

As implied in some other answers, you want to cut the onion with as few cuts as possible so you are releasing as little of these gases as possible. You want clean cuts.

• Your blade should be sharp. Dull knifes will tear open more of the onion and release more gases
• Use a straight blade. Serrated blades tear and grate and release far more of these gases
• Less motion is better. If you use a hand-held knife or a mechanical chopper that goes straight down, this is much better than using a rotating saw like some restaurants and delis use.

Answer 14

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.

Answer 15

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.

Answer 16

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

Answer 17

Keep your face away from the onion. Seriously! If you just move your head so it isn't directly above the onion when you cut it, the gasses that would normally go into your eyes won't and you won't cry.

Answer 18

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.

Answer 19

Cutting fast with a good sharp knife works well for me. A couple times I tried wearing a swimming mask and a snorkel (I learned that from watching "Diva" all those years ago) and that worked but is overkill most of the time.

Answer 20

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.

Answer 21

Just chew a gum while cutting it.. u will not tear a bit.. its a master secret.. trust me..

Answer 22

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

Answer 23

Use a gadget that chops it for you.

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

Answer 24

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

Alex . Italy

Answer 25

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

Answer 26

If you have a gas hob, light it and cut the onion next to it. I think that the hot air sucks the vapours away.

Answer 27

I have had some success just keeping the knife wet (though I agree that using a really sharp knife is probably the single most important factor). So just dip the knife in water or run it under a tap after every few cuts.

Answer 28

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.

Answer 29

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

Answer 30

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.