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The onion has been traced back as far as the Bronze Age and was worshipped by the Ancient Egyptians (and eaten by the Israelites during their bondage in Egypt). Onions were rubbed over the muscles of Roman gladiators, used to pay rent in the Middle Ages and eventually brought to the Americas, where today we fry, caramelize, pickle, grill and generally enjoy them.
Many of us burst into tears when we cut into one, too. It’s the price we pay for onion-y goodness. Here’s a play-by-play breakdown of how we go from grabbing a knife to crying like a baby:
1. When you cut into an onion, its ruptured cells release all sorts of goodies, like allinase enzymes and amino acid sulfoxides. The former breaks the latter down into sulfenic acids.
2. The sulfenic acids, unstable bunch that they are, spontaneously rearrange into thiosulfinates, which produce a pungent odor and at one time got the blame for our tears. The acids are also converted by the LF-synthase enzyme into a gas called syn-propanethial-S-oxide, also known as the Lachrymatory (crying) Factor.
3. Syn-propanethial-S-oxide moves through the air and reaches our eyes. The first part of the eye it meets, the cornea, is populated by autonomic motor fibers that lead to the lachrymal glands. When syn-propanethial-S-oxide is detected, all the fibers in the cornea start firing away and tell the lachrymal glands to wash the irritant away.
4. Our eyes automatically start blinking and producing tears, which flushes the irritant away. Of course, our reaction to burning eyes is often to rub them, which only makes things worse since our hands also have some syn-propanethial-S-oxide on them.
It only takes about 30 seconds to start crying after you make the first cut, that’s the time needed for syn-propanethial-S-oxide formation to peak.
Why Don’t Green Onions Make Us Cry?
The onion’s relatives, like green onions, shallots, leeks and garlic, also produce sulfenic acids when cut, but they generally have fewer (or no) LF-synthase enzymes and don’t produce syn-propanethial-S-oxide.
How Do I Avoid Crying?
You guys owe me for this one. Since I usually go through a good deal of onions while cooking at home, I’ve been road testing some of the different methods the Internet suggests for reducing or avoiding the effects of the Lachrymatory Factor. Here’s what I tried:
Method #1: Chill or slightly freeze the onions before cutting, the idea being that this will change the chemical reactions and reduce the gas that is released.
Result: The onion from the fridge has me crying just as quickly as room temperature ones. The one that was in a freezer for 30 minutes leaves me dry eyed for a bit, but by the time I’m done dicing my eyes start to burn a little.
Method #2: Cut fast! Get the chopping over with before the gas reaches your eyes.
Result: Just hacking away at the onion, I get in the frying pan without so much as a sting in my eyes. The onion looks awful, though. Doing a proper dice, I take a little too long and start tearing up. If you don’t mind a mangled onion, this is the way to go.
Method #3: Put a slice of bread in your mouth, and cut the onion with most of the bread sticking out to “catch” the fumes.
Result: It seems the loaf of bread I have has gone stale. I stop the experiment and put bread on my shopping list.
Method #4: Chew gum while chopping. It keeps you breathing through your mouth, which keeps the fumes away from your eyes.
Result: This seems to work pretty well as long as you hold your head in the right position. Leaning towards the cutting board or looking right down at the onion puts your eyes right in the line of fire again.
Method #5: Cut the onions under running water. This prevents the gas from traveling up into the eyes.
Result: An onion in the sink is a hard onion to cut. I think Confucius said that. My leaky Brita filter is spraying me in the face and I’m terrified I’m going to cut myself, but I’m certainly not crying.
Method #6: Wear goggles.
Result: In an effort to maintain my dignity, I try my eyeglasses and sunglasses first. Neither do me any good. The ol’ chemistry lab safety glasses make me look silly, but help a little more. I imagine swim goggles would really do the trick, but I don’t have any. Any readers interested in testing this for us? We’d love it if you also sent pictures.
Method #7: Change your onion. “Tear free” onions have been developed in the UK via special breeding and in New Zealand via “gene silencing” techniques.
Result: My nearest grocery store, Whole Foods, doesn’t sell genetically modified produce or onions from England. Tonight, we eat leeks!
If you’ve got a burning question that you’d like to see answered here, shoot me an email at flossymatt (at) gmail.com. Twitter users can also make nice with me and ask me questions there. Be sure to give me your name and location (and a link, if you want) so I can give you a little shout out.
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Comments (51)
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Just thinking about cutting onions made my eyes start to water a bit…could be psychological :)
posted by Liz on 2-4-2009 at 12:46 pm
Man, I wish I could pay my rent with onions like in the Middle Ages.
I once was given the task of cutting up about 100 onions for a soup-kitchen type deal I volunteered at and I couldn’t stand it for more than 1/2 hour. I looked like I just found out my best friend died or something, with the way I was crying.
Next time I cut onions, I’ll wear my swimming mask to see how it works, though I normally wear glasses and my mask isn’t prescription, so I don’t know how smart that will be.
I’m at work and I swear I’m smelling onions right now.
My Captcha kinda fits with this topic: culinary Jackson
posted by Shelly on 2-4-2009 at 12:53 pm
Ventilation is the key. Best thing to do is cut your onions in a glove box. Failing that, a fume hood. If you don’t have access to a fully stocked chemistry lab, open some windows and/or just set up some fans while you’re cutting. Also, just as green onions and leeks have less thiol compounds, different varieties of onion have more or less. I’ve found that a chilled sweet onion barely registers a tingle in the eye, while a room temperature Spanish is almost like mace.
posted by Jack on 2-4-2009 at 1:01 pm
Goggles for use when cutting onion are actually available for sale, and from experience I can say that they work beautifully. (The brand I used was called RSVP.) While wearing them, I diced three onions—a process that normally would have forced me to stop at least twice to clear my vision— without so much as a tear. It was a revelation. As for looks, well, they’re not as bad as swimming goggles, although probably that’s a case of being damned with faint praise.
posted by Ben on 2-4-2009 at 1:06 pm
I had a friend who cooked a lot and swore that burning a candle nearby worked.
posted by Craig on 2-4-2009 at 1:07 pm
My eyes do not bother me as much if I am wearing contacts when I cut up onions.
posted by Joanna on 2-4-2009 at 1:10 pm
It sounds silly, but I put a matchstick over each ear with the heads pointing forward. Make sure your hair doesn’t flop in front of them. It seems to work best with the wooden matchsticks, not the flimsy ones you tear out of pack. I don’t know why it works, maybe it’s just psychological, but works for me every time.
posted by TC on 2-4-2009 at 1:13 pm
I never have any problems cutting onions. I wear contacts and only cry when I’m not wearing them…
Anyone else have that happen to them?
posted by Lore on 2-4-2009 at 1:14 pm
Your Brita water purifier is leaking too? I’m on my third one…they just don’t last very long.
posted by Heather Dawn on 2-4-2009 at 1:15 pm
I used to hate cutting onions, but Ive noticed that when I have my contacts in, it doesn’t bother me at all. Probably a slightly more sophisticated version of the goggles. :)
posted by Alisha on 2-4-2009 at 1:17 pm
I second (third, fourth,…) the results of chopping with contact lenses in.
posted by Betsy on 2-4-2009 at 1:29 pm
Since I’m the only one in my family that eats them, I don’t get to cook with them very often. But an aunt of mine said if you light a candle near where you’re cutting, it helps.
posted by Joe on 2-4-2009 at 1:33 pm
I wear contacts, so onions very rarely bother me. My husband wears ‘onion goggles’, and they work like a charm for him. Plus, it makes me giggle when he wears them. And for some reason, it induces us to sing The Flight of the Conchords’ ‘The Humans Are Dead.’
Nothing like shouting ‘Binary solo!’ at the top of your lungs while trying to to a proper dice.
posted by Alex on 2-4-2009 at 1:34 pm
The bread in the mouth trick has worked for me in the past. The only problem with it is if you have to cut for a long time the bread tends to gets nasty after about ten minutes or so. If you have to do a lot of cutting get a loaf of cheap white bread and just go to town. (For a dinner party I needed to cut ten onions. About four pieces of bread got me through it.) But watch when your trading out the bread for a new slice . . . just taking it away triggers the reaction.
reCaptcha: $2 Curry
posted by Nathan on 2-4-2009 at 1:38 pm
My dad owns a resturant and he says the chef holds a simple toothpick between his teeth while cutting onions. Something about the tension in the muscles of the jaw cause your eyes not to water.
posted by Kelly on 2-4-2009 at 1:45 pm
I would not want to mess my car up by cutting cutting them in the glovebox, Jack. I fail to see how that would help anyway, but I’m glad you’ve found something that works for you, and the mental image I have in my head makes me chuckle. (No, I know what you really meant.)
That’s a no go on the chestry lab/kitchen. The wife was totally against it. She said the bromothymol blue brought back bad memories.
posted by Admiral Byrd on 2-4-2009 at 1:50 pm
I agree with the ventilation. I have a ceramic stove top with the vent hood over it, so I set the cutting board there & do the onion chopping with the vent fan on full blast. Of course, this doesn’t work as well if you’ve already got hot things on the stove.
posted by Evan on 2-4-2009 at 1:53 pm
the bread trick… the toothpick in the teeth… they force you to breath through your mouth. I like to cook, and find that if i remember to be a mouth breather i cry a lot less.
posted by crybaby on 2-4-2009 at 2:00 pm
Chilled sweet onions never make me cry, but any other type has me splashing water in my face in seconds.
Recapcha: In trouser
posted by Rissa on 2-4-2009 at 2:09 pm
To go along with the running water trick:
My mom came home one evening and found me in a pool of tears after cutting only half an onion. She says to me, “Where’s your bowl of water?!” Apparently, she always has a bowl of water sitting next to the cutting board whenever onions are involved. It works!
posted by Ace on 2-4-2009 at 2:15 pm
I’ve noticed the contacts method too. When I wore them in high school, I was fine, but after I went back to glasses, it would only take about 5 seconds before I had to leave the room to clear my eyes.
The chilling method works pretty well for me, but ventilation is the best by far.
I might try the fast cutting method myself. My diced onions look horrible anyways :)
posted by heather on 2-4-2009 at 2:18 pm
This is where the “Nicer Dicer” comes in handy.
posted by Frank on 2-4-2009 at 2:20 pm
We cooked with a ton of onions back in Switzerland and tried multiple solutions, sometimes several at a time. Cold onions + candles + goggles… Out of all of the remedies, we either let the contact-wearers do the chopping or don ski goggles. The goggles were a particular favorite and I’m sending in our lovely cooking fashion.
Also, a chef told me once that the flatter onions were less acidic and more sweet, usually less tear-inducing.
posted by Luz on 2-4-2009 at 2:29 pm
I believe my contacts exacerbate the problem, rather than alleviate it. Think my recaptcha is onto something. “gas speeds” it says; perhaps working in a vacuum is the only viable way to cure onion tears.
posted by tears of joy of cooking on 2-4-2009 at 2:30 pm
Buy a mandoline… preferrably one with a hand guard / shuttle (you want to keep your fingers). Keep you head away from the onion. You can get your onion cut quickly, neatly and into your pot/pan/whatever before the gas starts to affect you.
To dice with a mandoline, use a julienne setting. Pull back against the julienne blades, rotate left 90 deg, push forward, pull back, rotate right 90 deg, push forward. Repeat until done.
http://www.wikipedia.org/wiki/Mandoline
posted by Jason! on 2-4-2009 at 2:51 pm
As a couple people have said before me- contacts make all the difference in the world, when it comes to cutting up onions and shallots. To the point that, when I am at my parent’s house, I always offer to cut the onions up for what ever meal we are having. Those few times that I forget and just wear my glasses… ouch!
posted by Karen on 2-4-2009 at 3:07 pm
It helps if your knife is extra sharp. If it is at all dull you will rupture more cells and release more of the “make you cry” gas.
I am obsessive about my knives being sharp and I hardly ever cry while I cut onions (which I do almost every night). Although I also wear contacts – something I had never thought about before…
Hmmm…
posted by mara on 2-4-2009 at 3:15 pm
I remember MentalFloss doing a link on Morning Cup O’Links about how to slice an onion so you don’t cry- You know the “stringy” end, where the root system was? If you cut OUT in an inverted conical shape that part of the onion, you will bypass the greatest concentration of cry-inducing chemicals, leading, therefore, to a cry-free onion cutting experience without looking goofy in goggles. It worked for me. Maybe someone else can substantiate this method?
posted by Ashley on 2-4-2009 at 3:21 pm
Good call Mara. I was going to suggest the same thing. A sharper knife definitely reduces on the number of tears produced when cutting in to onions.
posted by Nick on 2-4-2009 at 3:39 pm
I’d like to point out (as a kitchenware distributer)that your model is cutting the onion with what appears to be a boning knife with a yellow handle to indicate that it is only supposed to be used on raw poultry. In other-words, this is a food safety no-no. She should be using a green handled cooks knife.
posted by Mandragora on 2-4-2009 at 3:59 pm
Cutting near a flame works, it burns off the fumes that form the acids. Also, I agree that a sharp knive makes all the difference in the world.
posted by Neil on 2-4-2009 at 4:05 pm
Just breathe through your mouth. Try not to breath through your nose – and don’t stand directly over the onion. And if you use them all the time, you get pretty good at cutting them fairly quickly. It just takes practice to not cry when you’re cutting them up.
posted by Steve on 2-4-2009 at 4:16 pm
When I wear my contacts I never have problems with crying while cutting onions. If I wear my glasses though, it’s tear city. I think the contacts definitely block the fumes from my corneas.
posted by Jenn on 2-4-2009 at 4:43 pm
I worked in a Deli and had to cut onions every morning for prep and my co-worker and I tried everything. We found that if you turn the oven on and leave the door open so the hot air comes out next to where you are cutting it helped. I know it sounds crazy but it really did work. Also running the knife under really cold water before cutting the onion and randomly during the process helps also. Something about the chilled knife makes the fumes not as bad when you start slicing.
posted by Nicole on 2-4-2009 at 5:59 pm
@ crybaby: actually they way I do the bread trick I end up breathing through my nose. I use my lips to hold the bread. I don’t know why it works . . .but at least for me it does.
posted by Nathan on 2-4-2009 at 6:10 pm
I haven’t once cried cutting onions with my contacts in…my glasses on instead is a different story entirely! I figure it is because they act as little cornea coverlets.
posted by Kali1901 on 2-4-2009 at 8:36 pm
I chop my onions in the food processor. I can pulse them to whatever size I want and I don’t have to be right over them.
posted by Tricia on 2-4-2009 at 9:14 pm
If you have contacts wear them while cutting onions.
posted by Lorelei on 2-4-2009 at 9:32 pm
One word…Vidalia’s. A ‘no tears’ solution. A seasonal product, yes. Just tie them (a knot between esch one) in a, preferably unused, leg of pantyhose. They’ll keep in your pantry for a long time.
Additionally, how do you get onion smell off of your hands? Wash your hands with soap and…a stainless steel spoon in your hands. It works! Why? Don’t ask me. It’s a mystery…errr, maybe.
Some mysteries must remain just that, a mystery. Otherwise, what would we have to speculate about?
posted by Drew on 2-4-2009 at 10:01 pm
Further to what Drew says, I have always found that putting a teaspoon in your mouth while cutting onions really helps. It may be psychological but it stops me from crying.
You look a bit stupid and if you are a sucking on a spoon for a long time you may start to drool, but I’d argue that both of those things are infinitely preferable to that awful stinging and crying.
posted by Eloise on 2-5-2009 at 1:15 am
Wearing contact lenses prevents eyes from burning or watering. I used to cut onions regular at a former job, and on days I wore contacts, I had no eye irritation from the onions. Rinsing the onions well in water seemed to help, too, but contacts were the best bet.
posted by Cory on 2-5-2009 at 2:14 am
I agree with the candle comments. I’ve always heard (and done this myself — works great) that you should light a match right next to where you’re cutting the onion, just before you do it. The reaction seems to neutralize the stuff the onion puts out. Works great, and hey — the sulphur smell is wonderful anyway! Mmmmm…
I figure a candle works too, it’s definitely the burning in the air that’s sucking the stuff away…
posted by Moira on 2-5-2009 at 4:07 am
Over Chanukah I had to grate onions and I always cry. I put my swim goggles on and voila! No tears. Of course I wear glasses and had to put them on over the goggles so I looked ridiculous. So, you will not be getting a picture of that.
As for the picture on the top, it is freaking me out. Always put down the knife and then wipe your eyes!
posted by Jenna on 2-5-2009 at 9:41 am
use a ceramic knife. I tried it at the promotion counter of Kyocera ceramic knives and despite chopping several slices of onion in the worst way possible (to rupture more onion cells and thus produce more of that tear-inducing gas) and placing all of them right under and in front of my eyes, they failed to make me cry.
posted by kajong on 2-5-2009 at 10:57 am
I HATE onions (vile weeds), and find that not cutting any onions works best for me. Not buying them, not eating them, don’t even have them around the house.
posted by jonny on 2-5-2009 at 11:18 am
In an episode of The French Chef where she’s making French onion soup, Julia Child says that keeping your knives sharp helps cut the onion faster and reduces the amount of liquid that sprays up from the onion. Therefore, you cry less. I noticed that when I got new (really sharp) knives, I didn’t tear up at all when cutting onions.
posted by ames on 2-5-2009 at 12:02 pm
Reference the French film “DIVA.” The character chops onions while wearing a snorkle! Maybe this works?
posted by Lauren M on 2-5-2009 at 2:04 pm
I chop a lot of onions, and I have usually cried, but so what. When I chopped a lot of them or I didn’t want to ruin make-up, I put on my ski goggles. (Sorry, I don’t have any pictures.) They work great, but I really had to bend my head down to see what I was doing over the edges of the goggles.
BUT, just before Christmas I saw onion cutting glasses for sale – the same RSVP brand mentioned above – and they are perfect. Much easier to put on than ski goggles and look a little less silly, too. Now I wear them for all onion chopping with no tears. In fact, once they are on, I usually keep them on through the carrot, celery, and other vegetable chopping. I kind of like looking silly, as long as I’m not uncomfortable.
posted by Jean on 2-5-2009 at 3:54 pm
I know I’m the gazillionth person to make this same comment, but I also wear contacts and have never had a problem cutting onions. I guess the contacts help block the chemicals…?
posted by CK on 2-5-2009 at 4:30 pm
I don’t have contacts and I do have loads of problems with chopping onions. Have even more problems eating them… I could live the rest of my life without any onions and not miss them (although sauteed are nice enough); having other people in my life means I do chop onions… rinsing the knife often during the chopping helps tremendously- slow you down but it’s worth it.
posted by ann on 2-6-2009 at 6:03 pm
What works best for me is sitting outside in the winter cutting them — i think something to do with the cold weather or slight breeze stops the gasses from reaching my eyes.
posted by mary on 9-29-2009 at 6:37 pm