)
)
In the blink of an eye—quite literally—chopping an onion can leave you in tears. Far from mere kitchen annoyance, this teary spectacle is a clever biological defence mechanism. Let’s peel back the layers and discover why onions make us weep, and how to turn the tables on these lachrymatory agents.
The Chemistry Behind the Tears
When you slice into an onion, you rupture its cells and unleash a cascade of reactions. The key players are:
ALSO READ: The right way to store onions so they last longer
)
)
)
Alliinase: an enzyme that, once freed, converts sulphur compounds stored within the onion into sulphenic acids.
Syn-propanethial S‑oxide: the volatile gas formed from those sulphenic acids. This is the true culprit—when it drifts up to your eyes and meets the moisture there, it forms a gentle sulphuric acid mist, stinging your corneas.
)
Your eyes, ever the gallant guardians, respond by flooding the area with tears to dilute and wash away the irritant.
Why Some of Us Sob More Than Others
Not all tear ducts are created equal. Individual sensitivity to syn-propanethial S‑oxide varies, so:
ALSO READ: Onion benefits for skin: 4 reasons why you should apply onion juice on your face
Those with more delicate eye membranes or more copious tear production will feel the burn sooner.
If you’re prone to hay fever or wear contact lenses, your eyes may already be on high alert, ready to shed an ocean at the first hint of irritation.
Six Clever Tricks to Chop Without the Crying
Pop them in the fridge for 30 minutes. Cooler temperatures slow down alliinase activity, so fewer irritants reach your eyes.
Sharpen Your Blade
A keen knife inflicts a cleaner cut, damaging fewer cells and releasing less lachrymatory gas.
Cut Under a Splash
Work beside your sink or submerge the onion in water. The vapour disperses less readily, sparing your eyes.
)
Let in the Fresh Air
Open a window or switch on an extractor fan. A gentle breeze carries the gas away before it can strike.
Don Your Goggles
It might look unorthodox, but snug-fitting goggles are the surefire way to keep onion vapours at bay.
Embrace the Food Processor
READ ALSO: 6 refreshing things to do instead of reaching for your phone when you wake up
By enclosing the chopping process, a processor traps most of the gases—just remember to clean it promptly!
)
Fun Fact
Wild onions evolved this tear‑inducing trick over millennia to deter animals and pests. Inadvertently, they also ensure we cook them quickly—so we miss fewer nutrients!
Next time the mere thought of onion‑induced tears sends you fleeing, remember it’s all science (and a touch of evolutionary cunning). Armed with these simple techniques, you can conquer your next recipe with dry eyes and a triumphant grin. Happy chopping!