We’ve all been teary-eyed when helping chop onions in the kitchen. No matter what we wear or which onions we choose to chop, it seems like we’re stuck with crying over onions as a curse that we won’t ever lift. Or will it?
Discover the secret to chopping onions backed by science, and feel relieved that there is a dry, tearless future.
What scientists did
When onions are cut, they release a compound called synpropanethial-S-oxide that triggers nerves responsible for producing tears. To find an alternative, tearless way to chop onions, a team of researchers at Cornell University in the U.S. decided to study how the compound is released and ways to minimise its effects on our eyes.
Researchers coated onions with a black spray paint to help them visualise what was happening while they chopped the onions, and also for tracking purposes. They also set up a high-speed camera (some serious stuff). Next, the group decided to use a custom guillotine to slice the black-coated onions. They experimented with speeds, ranging from 0.39 to 1.9 metres per second (1.3 to 6.5 feet per second), and blade thicknesses between 5 and 200 millimetres.
They found the thinner, sharper blades that moved more slowly and with less energy produced fewer droplets. The ticker, duller blades moving at faster speeds with more energy, produced an explosion of droplets, easily propelled into the eyes.
They agreed that duller blades moving at higher speeds bent the onion’s skin before even slicing through it, resulting in a build-up of pressure that resulted in a more powerful release of juice. In fact, they found that duller blades produced as many as 40 times more particles than sharper, thinner blades, while faster cutting speeds produced up to four times as many droplets as slower speeds.
Additionally, the group also experimented with refrigerated and room-temperature onions. The refrigerated onions released a larger volume of droplets when compared to the room temperature ones.
So how can you use this at home?
- Sharp blades only: Sharper and thinner blades produce cleaner cuts and less cell rupture
- Slow and steady wins the race: Cut slowly and gently; don’t rush. Slower cuts reduce the force that ejects tear-jerking droplets.
- Room-temperature for the win: Use room-temperature onions for slicing – the science shows refrigerated onions produce a whole lot more irritating compounds.
Who knew that the solution would be this simple? Keep those thick, dull blades away from the chopping board, and those goggles for the pool!
