How to Chop an Onion without Crying | Co-Lab Pantry

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How to Chop an Onion without Crying

Published on
By Tehya Nicholas

The age old question, finally answered.

Ah onions, how we love you so. You add a depth of flavour to almost every dish. When you fry in olive oil, you make our house smell delicious. But why, dear onion, must you make us cry with your spicy onion vapour?

We’ve all been there: slicing open a brown onion for a bolognese, only to be inundated with tears the moment chopping begins. At best it’s an embarrassing folly, at worst a genuinely painful and dangerous situation (knife, tears… you get my drift).

So first of all, what the heck is going on to make our eyes leak this way, and more importantly, how do we make it stop?

Onions are special little guys chock full of chemicals and amino acids. One such amino acid, sulfoxides, is the culprit to your eye leak. When we slice into an onion’s skin, we are essentially damaging it, which causes the onion to convert sulfoxide into sulfenic acid. That then rearranged itself into - brace yourself - syn-propanethial-S-oxide. Imagine it like a revenge-fart, shape shifting and making its way through the air towards your eyeballs. Cue tears.

There are a couple of methods tried and tested by chefs and home cooks to make this all go away. Without further ado, here are the ones that work.



For those with a little bit of time up our sleeves, freezing an onion in advance is an effective and easy way to cure the onion blues. For best results, peel the onion first and pop it in a ziplock bag. When the time comes, whip it out and get cutting. No tears, no dramas.


It may sound ridiculous, but putting a piece of bread in your mouth while you chop is proven to be effective in reducing onion-related tears. The bread literally soaks up the sulfenic compounds before it can reach your eyes AND you get a snack.


Rebel Sport should look into an onion-specific range of goggles because this is the single-most successful way to stop the waterworks. You’re going to look like a fish out of water, but the result? One cleanly diced onion, one fresh faced cook. Worth it.