Tips for Cutting Onions Without Tears
Ask five people how to cut onions without crying, and you’ll probably get five different answers. Here are some that actually work (and a few that don't!)
Just about every dish I make starts in more or less the same way: I sauté some diced onions (or, more typically, onions and garlic). That means I’m peeling, slicing, and mincing onions on my cutting board at least three or four nights a week. And I’ve been doing so for decades.
Somewhere along the line, I simply gave up on trying out new ways to chop onions without crying. Some days, I get off scot-free (score!), while other times, the waterworks come on as if I’ve just watched Terms of Endearment again. I never paid enough attention to detect any discernible patterns — until now.
Why do chopped onions make you cry?
In a word, biochemistry. In a few much-more-complicated words, when you cut, crush, or otherwise damage the cell walls of an onion, a naturally occurring enzyme called alliinase comes in contact with another molecule, sulfenic acid. When this happens, it creates a volatile lachrymatory factor or "LF." (There are many, many more polysyllabic scientific words involved like "syn-propanethial-S-oxide," which is an irritant, but I didn’t do well enough in high school chemistry to use them confidently). LF is a defense mechanism for the onion — what we perceive as the onion smell wafts into the air and burns the predator’s eyes. “It’s similar to tear gas,” one scientist told The New York Times. Another put it this way: “The biochemical pathway that gives onions their savor is part of the chemical warfare against microbes and animals.”
Onions, then, are not messing around.
But they’re delicious, so persevere we must.
Onion-cutting tips that work (more or less)
A few straightforward techniques can help control how much LF is a factor.
Chill your onions
Take your pick — you can let your onions chill in the fridge, pop them in the freezer for 15 minutes, or just dunk them in an ice water bath for a little while. Getting an onion nice and cold helps prevent eye irritation by reducing the amount of chemicals released through cutting.
Fan away the fumes
Cut your onions near your range hood or a small fan. The circulating air will blow the LF away from your eyes and help keep you tear-free.
Cut under cold water
This works like chilling your onions and using a fan — cold running water both lowers the temperature and reduces the amount of LF reaching your eyes. Logistically, it might be awkward, though.
Sharpen that knife
Sharp knives are a must. Full stop. But when it comes to onions, a good knife does more than make slicing easier and safer. It helps minimize the damage to the cells of the onion, which can slash the release of LF.
Work on your knife skills
Hone your skills to work more quickly and confidently, and there will be fewer tears. Here’s one method Martha Stewart recommends:
Cut it in half from stem end to root end. Set one half aside, cut side down, on your work surface. Cut off the stem end of the other half and peel it. Place it cut side down on the cutting board and make vertical cuts along the veins of the onion, without cutting through the root end, which holds the onion together as you work. Make a few horizontal cuts from the cut stem end toward the root end. Then chop across the onion from the cut stem end to the root end.
Cut near an open flame
Another tip from Martha, with so-so reported success: slice your onions near an open flame. The fire is supposed to draw in and burn off some of the LF before it reaches your eyes.
Cut off the top of the onion
Allegedly, the rough root end of the onion is where most of the enzymes and molecules are concentrated. Again, you might achieve only middling success with this method.
I mean, you can. There are even hideous onion goggles for sale. But you shouldn’t need them.
Onion-cutting tips that don’t really work
Your aunt, best friend, or next-door neighbor will undoubtedly swear by one of these methods. Just smile and nod.
Hold a piece of bread in your mouth while you chop
The idea seems to be that the bread can potentially absorb some of the LF before it reaches your eyes. Dubious.
Hold a spoon in your mouth while you chop
Allegedly, the LF will bind with the metal of the spoon. Unlikely.
Microwave the whole onion first
This not-so-great idea is similar to the one behind chilling the onion — supposedly microwaving interferes with the chemical reaction. More likely, it’ll just make your whole kitchen reek of onion.
Breathe through your mouth
Supposedly, the LF will enter your mouth before it can irritate your eyes.
Chew gum while you chop
Chewing gum is supposed to make you breathe through your mouth (see above).
With these new onion-defense tips in your arsenal, you don’t need to shy away from any raw onion-heavy meals or recipes. In fact, bring ‘em on.
How to Caramelize Onions
For this back-pocket recipe, all you need are six large onions, your recently sharpened knife, and some clarified butter. Food Republic’s Jess Kapadia has her own trick for cutting raw onions without watery eyes: “Stick your tongue out while you’re slicing.” Try it at your own risk.
Pickled Red Onions
I am never without a small jar of pickled onions in my fridge — they’re perfect for impromptu Mexican and Indian dishes or if I need to zhuzh up a sad salad. While my preferred combo is just thinly sliced onions, lime juice, and a pinch of salt, David Lebovitz takes his to the next level with white vinegar, sugar, and proper pickling spices.
French Onion Soup
An all-time fave. This recipe from Williams-Sonoma asks for 2 1/2 pounds of yellow onions. If you want to take it up a notch, they recommend a mix of red, white, and sweet onions such as Vidalia.
Low Fat Baked Onion Rings
“Low fat” and “onion rings” are two concepts I didn’t really expect to see anywhere near each other, but this recipe from Skinnytaste makes it work. The secret? Baking them. One medium onion fills a single baking sheet and gives you two appetizer servings, so I’d suggest doubling for good measure.
It’s like the onion rings of India — deep-fried, generously spiced (but not spicy), and delicious. Three onions yield four to six appetizer servings.