Stop Crying Over Chopped Onions

February 17, 2016

As soon as my knife slices through the skin of an onion, I start to look like an extra in a Greek tragedy: a mascara-streaked mess with stinging-red eyes. It's around this point during dinner prep that I flee the scene in search of a gas mask and my boyfriend—who is somehow immune to onion's tear-jerking qualities—takes over.

Photo by James Ransom

I've tried every trick in the book: a bandana tied over my entire face, breathing through my mouth with my tongue out. (The internet told me this would work; it did not.) I've even employed a pair of old swim googles, which only made me look like a less-charming, very upset version of Hugh Grant in Notting Hill. So while watching our Test Kitchen Manager, Josh Cohen, chop a mountain of onions, I asked him for his secret. The answer? An extremely sharp knife.

He explained:

"If you imagine the onion cells on a microscopic level, then a dull knife is like smashing through them with a hammer, crushing the cell walls and releasing vapor. If a knife is sharp, it slices through these cells cleanly."

Some quick research confirmed his explanation: The duller the knife, the more enzymes are crushed and the more irritants are released. My thoughts drifted to my knife of choice: a two-year old IKEA chef's knife that's never met a sharpener in its life. At the expense of becoming a wobbly tear-streaked mess, I put the theory to the test.

Test 1: The Dullest Knife I've Ever Known

The knife: My aforementioned IKEA knife, which at this point (several years and even more roommates down) is about as efficient at chopping herbs as a mortar and pestle.

How it performed: Last night, slicing red onion rounds for Ottolenghi's red onion salad, I got about three crosswise slices in before my slightly stinging eyes escalated to fresh-off-the-heels-of-a-break-up tears. Game over.

My stopping point with our test kitchen's dullest knife.

Test 2: Our Test Kitchen's Dullest Knife

The knife: Food52's test kitchen's dullest knife—meaning Josh won't use it, but that it's still probably ten-thousand times better than own.

How it performed: About one minute into chopping a yellow onion, I was feeling fairly confident, but as soon as I'd gotten my onion pieces into a rough dice 20 seconds later, a wave of fumes hit me and I had to step away to give my stinging eyes a break. A red onion was slightly more difficult, but I successfully made it to a rough chop without crying!

My stopping point with our test kitchen's sharpest knife.

Test 3: Our Test Kitchen's Sharpest Knife

The knife: This is the sharpest knife we have in the kitchen—a brand-new Miyabi that can practically cut an onion just by looking at it.

How it performed: This was possibly the happiest onion chopping experience I've ever enjoyed—around two minutes in, once I'd chopped a yellow onion finely, I finally felt a faint sting. The same proved true of a red onion. But beyond that, I happily chopped without any pain or tears—an allium miracle!

The takeaway: Never will I ever chop an onion with a dull knife again.

Our sharpest sharps:

Do you have any tips for chopping onions? Have you found the sharp knife trick to be true yourself? Tell us in the comments below!

See what other Food52 readers are saying.

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I eat everything.


Jodi V. March 17, 2016
The kit candle truck works for me too. Even if I forget to light it ahead of time... As soon as the tears start I can go get a candle, light it near the cutting board, and no more stinging eyes! Makes cooking a more romantic experience, even though I'm just cooking for myself :)
Nanne February 23, 2016
cutting the onion and letting it sit in the fridge for awhile (the longer the better) is the only thing that has worked for me and my dull knives :).
Catherine L. February 22, 2016
I trick I heard about years ago is to have a candle lit right by you. It works great for me.
Jane February 22, 2016
Thanks for this!!! I never had a problem chopping onions at my old place but when I moved in with my husband during a kitchen reno, we only kept out an older, pretty dull knife while everything else is in storage. I can't get through an onion without tears down the face and now I know why! Makes perfect sense.
Shruthi February 22, 2016
Such a useful tip! Thank you!

willgoh2 February 21, 2016
If you can remember to, pop the onion in the fridge for about 15-20 minutes to make it cold. For some reason, a cold onion doesn't give off as much of the tear inducing fumes. I do this with a sharp knife each time.
Kate February 20, 2016
Hold a match or two in your mouth! The end of the match somehow absorbs the onion juice that makes you cry. Works so well!
Mimi February 19, 2016
Wipe cutting board with vinegar before starting... It works!
Noreen K. February 18, 2016
When I dice onions I put my cutting board on the grates of my stove and turn the fan on high. It is important to make sure the stove is off when I do this, but it works great and no tears.
Wendy V. February 18, 2016
No cry onion chopping :
1. Turn on hood fan/ vent
2. Place cutting board between self and hood fan. (Chop on top of burners if necessary!)
3. Use a dangerously sharp knife!

No hood fan? You could try just at an open window with a fan blowing out!

How's I. February 18, 2016
As others have mentioned, contacts are excellent for keeping your eyes dry and free from the sting; I don't wear them, but anyone I've ever known who has could chop onions all day long with no issues. My personal preferred way is a cheap pair of "shop goggles," like the kind you might see in a junior high chemistry class. I tried swimming goggles myself- they were ok, but definitely not great- but the $4 shop goggles, which I bought at a hardware store, have worked for me better than anything, and they're what I always recommend to others (besides using the sharpest knife you have, of course!).
Also, I second what secondbasil said- chewing gum really does work. I've been told that it's because you breathe through your mouth more than you normally would, but I've tried breathing only through my mouth with no gum and it was considerably less effective.
Andy M. February 17, 2016
While it's true a sharper knife will reduce tears for the reason you gave, a sharp knife can't guarantee a tearless experience. The bottom line is to keep any fumes away from your eyes. No fumes=no tears. Swim goggles may not be glamorous but will do the job. Then again, all those years aren't glamorous either.
Leslie S. February 17, 2016
Swim goggles didn't work for me! I found that the fumes still got me through my nose. Maybe it's time I invest in full-coverage goggles...
Amanda S. February 17, 2016
Yes! Biting a piece of bread (adorable, I know) actually works really well, absorbing the onion aromas or some other chemistry-magic I don't understand.
Leslie S. February 17, 2016
I believe it! I recently scratched my ear with a chile pepper hand and I'm happy to report that bread in your ear (adorable, I know) also works wonders for chile burns! #breadmagic
Smaug February 17, 2016
A sharp knife is also considerably less likely to chop off fingers- you really shouldn't cut anything with a dull knife- onions are particularly prone to knife slips if they're a bit old.
Ali W. February 17, 2016
Try chewing gum, I swear it works!
Corene W. February 17, 2016
When I wear my contacts lens my eyes never burn, but when I wear my glasses(most of the time) the burn is awful.
Olivia B. February 17, 2016
That's my trick, too! I wear contacts and never get onion tears. One lucky upside to terrible vision :)