Scientific Study Debunks Onion Myths: Sharpness, Not Temperature, is Key to Tear-Free Chopping

The key breakthrough from the high-speed imaging was the realization that the irritating chemical is not released in a single, homogeneous plume, but in two distinct phases that are directly tied to the severity of the cellular damage. The initial phase involves a fast, explosive layer of gas or 'mist' that jets immediately from the surface of the freshly cut tissue, followed by a secondary, slower release of lachrymatory factor carried within liquid droplets. The study definitively established that a slower, high-impact cutting motion—or, more critically, a dull blade—significantly increased the energy and volume of the highly irritating mist particles released into the air. This meant the way the knife interacted with the onion tissue was the primary determinant of the chef's watery fate.