Why Does Cutting Onions Make You Cry?

Who hasn’t been brought to tears by onions? We certainly have — but that’s because we love them so darn much. For many other people, it’s because they decided to cut one open. And, for just as many people, the reason why cutting into that sweet, sweet onion sets the waterworks flowing is a mystery. 

Let us solve it for you. 

It’s Not an Emotional Reaction — It’s a Chemical One

Let’s start by reviewing a little onion anatomy. At the end of the day (and at the beginning as well…and really through the entire day, actually) an onion is a bulb. It grows under the ground. You know what else hangs out under the ground? Little critters who love to nibble on bulbs, like voles, moles, and groundhogs, oh my!

So, onions have a defense mechanism to protect them from all those unwanted nibbles. Enter chemical reactions. 

When the skin of an onion breaks, whether from a nibble or your favorite kitchen knife, it begins to release a combination of enzymes and sulfenic acid. When these two compounds come together, they create an extremely irritating gas called propanethial S-oxide. When this gas is released, it evaporates quickly and finds its way to — you guessed it — your eyes. When it hits the water that covers the surface of your eyes, it turns into sulfuric acid.

Now, here’s the thing. Just like the onions have a defense mechanism to keep them safe, so do your eyes. When the nerves in your eyes detect the sulfuric acid, they know they need to flush it out. Cue the tears. 

So, What’s an Onion Lover to Do? 

There are a lot of different ways that people say you can help yourself out in the onions and tears department. How effective these strategies are depends a lot on your own genetics, on the onion you’re cutting, and the universe in general. 

  • Put a barrier between you and that nasty onions gas by slicing onions under clear plastic or glass. 
  • Cut onions under a vent or fan to help disperse the gases away from your eyes. 
  • Freeze the onion before cutting it. 
  • Cut the onion under the water. 
  • Wear goggles. 
  • Cook the onion, then slice it. Cooking deactivates the enzymes.
  • Rinse your eyes after cutting to help flush out the sulfuric acid. 
  • Use a cold compress or even cucumber on your eyes to reduce the irritation after cutting (another vegetable to the rescue!).
  • Try clearing your eyes with some eye drops. 

The only sure fire way to not cry when cutting onions is to not cut them in the first place. 

Let Us Cut Your Onions for You

If you’re still chopping onions, it’s a crying shame! Why not let Gills Onions do the hard work for you. It doesn’t matter if you’re a chef whipping up your signature dish or a home cook experimenting with a new recipe. Our sliced and diced, ready-to-use, value-added products save time — and tears — while delivering the best onion flavor there is. 

Ready to try onions grown “The Gill Way”? Contact our sales department to learn more.