It’s one of the most classic kitchen clichés: chopping an onion leaves you blinking back tears. For most home cooks, it’s a rite of passage — and it can quickly turn dinner prep into a teary-eyed ordeal. But it doesn’t have to be that way. With a few simple tricks and a little science, you can chop onions like a pro — no tears, no fuss.
Why Do We Cry When We Chop Onions?
Onions are a staple ingredient in cuisines around the world — from India to Italy and everywhere in between. That’s why you’ll find delicious onion recipes in all sorts of global dishes. But no matter where you cook them, onions are known for triggering tears.
That’s because onions contain sulfuric compounds and enzymes stored in separate parts of the plant’s cells. When you slice into an onion, these elements react to form a gas that irritates your eyes and nose — triggering that all-too-familiar stinging sensation. Thankfully, there are easy ways to reduce the impact.
How to Chop an Onion Without Crying
The root of the onion holds the highest concentration of those tear-inducing chemicals. To minimise exposure, cut the onion in half from top to root, but leave the root end intact while slicing. Here’s the step-by-step method:
Peel the onion and cut it in half through the root.
Make vertical cuts down the onion, stopping just short of the root.
Turn the onion 90 degrees and slice horizontally to dice.
This technique reduces chemical release while helping you get evenly chopped pieces for everything from stews to burgers like this steak and caramelised onion burger.
Pro tip: Don’t want to chop onions at all? Pre-diced frozen onions are a convenient (if slightly pricier) alternative.
Bye, Bye Tears: Onion-Chopping Tips and Tricks
Still tearing up despite your best efforts? Give these methods a try — one of them might just be your personal solution:
Chill the onion in the fridge for 30 minutes to slow down the chemical reaction.
Use a sharp knife to cleanly cut the onion without crushing its cells.
Microwave the onion on low for 60 seconds to neutralise the enzymes before chopping.
Hold a match (unlit!) between your teeth — some swear it works by drawing the gas away.
Wear onion goggles to physically block the irritants from reaching your eyes.
Onion Prep Made Easy: How to Peel and Slice Like a Chef
Different dishes call for different cuts. For saucy dishes like bolognese or mushroom and caramelised onion quesadilla, finely dicing the onion allows it to soften into the sauce. For onion rings or stir-fries, thin slices may work better.
To thinly slice an onion:
Peel the skin.
Cut off both ends.
Halve the onion vertically.
Lay it flat and slice vertically again, angling your knife slightly for even, elegant slices — perfect for recipes like caramelised onion and fetta chicken.
How to Cut a Spring Onion — and Other Smart Hacks
If you love onion flavour but want a milder, no-tears option, spring onions are a fantastic alternative. Use the white base for a deeper flavour during cooking, and save the green tops as a garnish for extra colour and taste.
Short on time? Keep a jar of onion marmalade in the fridge — it’s a smart shortcut to deep, caramelised flavour. Use it to level up your meals, like in this haloumi and caramelised onion burger or this elegant caramelised onion goat cheese and olive tart.
Chopping Onion FAQs
What is the best way to chop an onion?
Cut it in half from root to tip, leave the root end intact, then slice vertically and horizontally to dice evenly.
What is the hack for onion cutting?
Keep the root attached, chill the onion, microwave it briefly, or try onion goggles — all help reduce the sting.
Is there a right and wrong way to cut an onion?
Yes — cutting from root to tip helps hold the onion together and results in more consistent slices.
Do you cut or peel an onion first?
Always peel the onion first to avoid papery skin mixing into your dish.
What is the match trick for cutting onions?
Place an unlit match between your teeth while chopping. It’s an old-school hack, but some swear it helps redirect the irritant gas.