Why you cry when you chop an onion — and how not to

It's a conundrum: Onions add flavor to any dish, but chopping them always leads to tears. The last time I made onion soup it involved more weeping than back-to-back viewings of “Beaches” and “Terms of Endearment.” That said, the internet has layers of strategies to beat the bulb. Among them — wear goggles (badass but ineffective); hold an unlit match in your mouth (your cat will never respect you again); and cut under water (in a NYC sink? As if). And there are more where those bright ideas came from.

So what’s the best strategy? We asked Eric Block, a professor and author of “Garlic and Other Alliums: The Lore and the Science.”

He explains that onions contain a chemical irritant called syn-propanethial S-oxide — a self-defense mechanism that discourages “critters looking for a snack.” The act of cutting into an onion causes an enzymatic reaction releasing the irritant's volatile molecules into the air. “They evaporate, but not before getting into your eyes,” said Block. But they can take a roundabout route through your nose and mouth. Which is why it'd take a hazmat suit, not just goggles, when you mince.

One recommendation is refrigerating an onion for a few minutes before chopping because eye-irritating compounds are less volatile when chilled. But it can subtly change texture. "I'm not certain all chefs would like that idea," Block told the Daily News. His best tip: chop onions in a well-ventilated area, near a fan. “You'll blow the molecules away,” said the Onion Man, “and they won't get to your eyes.” Science! Tasty!