Do onions always make you cry? These tricks might change that

If you’ve ever found yourself weeping over the chopping board while preparing dinner, you’re not alone. Onions are a staple in Australian kitchens, adding depth and flavour to everything from hearty stews to fresh salads. 

But for many of us, the tears they bring are almost enough to make us swear off them altogether! So, what’s really going on—and how can you keep your eyes dry next time you’re dicing an onion? 

Let’s start with the science. When you cut into an onion, you break open its cells, releasing enzymes that react with sulphur-containing compounds. 

This reaction creates a volatile gas called ‘syn-propanethial-S-oxide’, which wafts up and irritates the eyes, causing them to water in self-defence. It’s the same chemical that gives onions their signature bite—and unfortunately, their tear-inducing power.

But don’t worry—there are a few tried-and-true tricks to help you keep the tears at bay. Here are three proven hacks, plus a bonus tip.

1. Use a really sharp knife

It might sound simple, but the sharpness of your knife makes a world of difference. A dull blade crushes and bruises the onion, releasing more of those pesky enzymes and sulphur compounds. A sharp knife, on the other hand, slices cleanly through the cells, minimising the chemical reaction and, in turn, your tears.

Tip: If you haven’t sharpened your kitchen knives in a while, now’s the time! Not only will it make onion-chopping easier, but it’s also safer and more efficient for all your cooking needs.

2. Chill the onion before cutting

This is one of those rare internet hacks that actually works. Pop your onion in the fridge for a few hours, or in the freezer for about 30 minutes before you need it. The cold slows down the enzymes and reduces the volatility of the sulphur compounds, meaning less of the tear-inducing gas is released.

Tip: Make sure the onion is chilled all the way through for best results. If you’re a regular onion user, consider keeping a few in the fridge at all times.

3. Cut onions in front of a fan

If you have a small desk fan or even a portable kitchen fan, set it up so it blows across your chopping board and away from your face. The fan disperses the onion vapours before they can reach your eyes. If you have a vent hood, chopping onions directly under it can also help, though a fan blowing sideways is usually more effective.

Tip: If you’re really sensitive, try combining this with the chilling method for double the protection.

Bonus move: Suit up with eye gear

It might look a bit silly, but wearing goggles (swimming goggles, safety glasses, or even lab goggles) creates a physical barrier between your eyes and the onion fumes. If you’re cooking up a big batch of onions for a family gathering or a week’s worth of meals, this can be a real lifesaver.

Happy chopping—and may your next meal be as flavourful as it is tearless!

Do you have a tried-and-true method for cutting onions without crying? Have you discovered a family secret or a quirky hack that works for you? Share your experiences and tips in the comments.

Also read: Pantry magic: An unexpected trick to keep onions fresh for months