Key Points
- Position the cutting board right next to an open flame, such as a stove burner or candle.
- The flame helps burn off or neutralize tear-inducing onion compounds before they reach your eyes.
- The tear-triggering agent is syn‑propanethial S‑oxide, which forms sulfuric acid in your eyes.
- Unscented candles are best if you choose to burn one, so there will be no extra fragrances to interfere with the cooking experience.
Martha Stewart is definitely THE queen of the kitchen. She has been teaching America how to cook for decades, and now she is surprising us once again with a simple kitchen hack that will save you lots of tears in the kitchen - literally.
Martha has a new trick that will prevent you from crying next time you cut into an onion. Follow Martha’s advice next time you are chopping onions. You may never cry from onion fumes ever again!
Why Do You Cry When You Cut an Onion?
The tears that fall when you cut an onion aren’t emotional; they are scientific! When sliced, onion cell walls rupture and unleash enzymes and sulfoxide compounds that quickly react to form syn‑propanethial S‑oxide, a volatile gas. When this gas meets the moisture in your eyes, it transforms into a mild form of sulfuric acid, which is what causes the stinging sensation and involuntary tears.
Martha Stewart's Method for Cutting Onions
Martha Stewart recommends chopping onions right beside an open flame. Whether that’s a stovetop burner or even a simple candle. The idea is that the flame helps capture and burn off the eye-irritating compounds released when an onion is cut, preventing them from drifting upward and causing tears.
While this is not a laboratory-proven solution, Stewart swears by the method, noting that during her catering days she could slice through “20 to 30 pounds” of onions without tearing up. It is a practical, low-effort hack that reflects her trademark blend of kitchen know-how and everyday ingenuity. That is why we love Martha!
Other Ways to Prevent Onion Tears
If a flame isn’t an option for you when you need to chop onions, there are a few other tear-stopping alternatives that Martha recommends.
- Chill the Onion – Refrigerate for about 30 minutes before chopping to slow enzyme reactions and reduce vapor spread.
- Use a Sharp Knife – Clean cuts minimize cell breakage, reducing the release of tear-inducing compounds.
- Improve Ventilation – Use a fan or range hood to blow irritating gases away from your face.
- Onion Goggles – A physical shield for your eyes works surprisingly well to prevent onion tears.
- Cut Under or After Water Soak – Submerging onions or cutting them under running water helps trap and dissolve the onion eye irritants.
+ Pro tip from me: Many people who wear contact lenses notice they don’t tear up as much (or at all) when chopping onions. That’s because the lenses act like a barrier, blocking the gas from directly reaching the eye surface.
Best Candles to Use When Cooking
If you want to use Martha Stewart's onion trick, be sure to grab a high-quality candle. Unscented pillar or taper candles are ideal as they burn steadily, have an open flame, and avoid introducing competing fragrances into your cooking space. You can see in her video that this is the type Martha uses.
Avoid candles enclosed in glass or hurricane holders, as the flame’s airflow should interact directly with the surrounding air for maximum effect.
The Easiest Way to Stop Crying When You Cut An Onion
Martha Stewart’s flame-side onion chopping is more than a quirky visual, but it is rooted in chemistry and airflow physics. By situating your cutting board near a flame, you are literally burning off tear gas before it hits your eyes. It doesn’t matter if you are slicing one onion or 30 onions like Martha, this easy but savvy pro tip can make cooking a tear-free experience.
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