If you have spent time in the kitchen, then chances are you have probably cut onions. If you have cut onions, then you have probably cried before and felt a stinging burn in your eyes. In fact, as a chef connoisseur myself, I have had my own encounters with tears caused of onions. In other words, cutting onions make us cry and feel a stinging burn in our eyes.
But WHY?
The reason why cutting onions causes us to cry is because onions, when cut, release a compound, called Propanethial S-oxide, that flies through the air and inevitable into your eyes. Propanethial S-oxide is responsible for that instantly recognizable sting in our eyes. Propanethial S-oxide and other compunds, specifically another form of Sulfuric Acid, irritates the Lacrimal Glands in our eyes and causes the irritation and stinging.
How Exactly does Propanethial S-oxide Irritate Our Eyes?
Propanethial S-oxide is a chemical compound that is made up of methionine and crystine, amino acids. When the onion is cut and the Propanethial S-oxide flys through the air specific enzymes mutate these amino acids into another form of Sulfuric Acid.
How Can You Prevent Onion Irritants?
The irritants in onions can be reduced or mitigated through several methods:
- Use a sharp, precise knife to slowly cut into the onion to avoid damaging the onion’s cells and releasing irritants.
- Cool the onion before cutting to suppress the scattering of irritants, due to the onion tightening while being frozen.
- Cut the onion into halves or quarters and soak them in water to dissolve the amino acids/irritants.
- Wear full-eye covering protection (Ex. goggles) to avoid getting the irritants into your eyes.
- Use a fan or wind-displacing item to blow the irritants away from your eyes.
Links to Similar Studies
- Japanese Central Customs Library
- Earth.com: Scientists Finally Learn Exactly Why Cutting Onions Makes Us Cry
- Phys.org: Physicists Determine How To Cut Onions With Fewer Tears
WiseWhys 
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