Cutting an onion releases the “tear” chemicals (photo Flagstaff Fotos).
An onion is a thing of beauty—until you slice into it and the fumes assault your eyes. But that doesn’t need to be. Here are some tips to minimize the impact of the acrid gas that’s released when you slice into an onion.
WHY DO ONION VAPORS BURN YOUR EYES?
Simply peeling an onion does not make your eyes water.
But once you chop, cut, crush or smash the onion, the onion’s cells break open, creating a chemical reaction. Enzymes called alliinases break down the amino acids (sulfoxides)in the onion and generate sulfenic acids.
These further react to produce a volatile gas known as the onion lachrymatory factor, or LF. LF diffuses through the air and activates sensory neurons in eye, causing that burning, stinging sensation.
It’s not dissimilar to the effects of tear gas. Tear glands come to the defense, producing tears to dilute and flush out the irritant. If you slice onions a lot, your eyes will become more tolerant (they may build up a tolerance to the LF).
The amount of LF differs among onion varieties. That’s why some onions are real “burners” and others are milder. Sweet onions, for example, grow in soils that are low in sulphur and don’t produce much alliinase.
NO-STING & LESS-STING SOLUTIONS
Our personal technique: For no sting whatsoever, wear swimming goggles (or any goggles). It works like a charm.
No goggles? These will help: