There's a Surprisingly Simple Way to Stop Crying Over Your Onions
When onions are chopped, they release a chemical mist called propanethial S-oxide that causes eyes to water. Scientists from Cornell University have discovered an easy method to reduce this effect.
Using sharper blades and cutting more slowly during preparation significantly lowers the amount of onion mist expelled, keeping eyes drier and kitchen surfaces cleaner.
Research Methods and Findings
Biomechanist Zixuan Wu and the team employed a mini guillotine, a high-resolution camera, and sensors to monitor droplets released as onions were cut. They analyzed the mist's properties in relation to knife sharpness, chopping speed, and cutting force.
"We found out the speed of the mist coming out is much higher compared to the speed of the blade cutting through," says physicist Sunghwan Jung.
As onion layers are sliced, two effects occur: a sudden burst of mist and a slower seepage of fluids through the layers. The study revealed that blunter knives produce many more droplets and faster sprays because they require greater force to break the onion skins, which increases pressure inside the juices.
Forceful, rapid cuts with dull blades cause droplets to travel even farther.
Summary
Using a sharp knife and cutting onions more slowly can greatly reduce the tear-inducing mist and help maintain a cleaner kitchen.
Author’s note: This research underscores how simple changes in technique can minimize the discomfort and mess caused by chopping onions.