A groundbreaking study at Cornell University reveals the science behind crying while chopping onions, offering a solution for home cooks to reduce tear-inducing chemical dispersal.
Slicing an onion releases tear-inducing chemicals into the air. The sharpness of the knife and the speed of the cut can affect how these droplets are expelled.
Onion chopping is a fundamental cooking skill that requires precision and patience.
To chop an onion efficiently, start by peeling and halving the onion.
Place the flat side down on a cutting board and make parallel cuts without cutting through the root end.
Then, make perpendicular cuts to create small pieces.
This technique reduces tear-inducing gas release and makes chopping easier.
A sharp knife is essential for smooth cuts.
When onions are cut open, they spray a mixture of sulphur-rich compounds into the air, one of which is syn-propanethial-S-oxide, a chemical that triggers the nerves in the eye responsible for producing tears. This phenomenon occurs because the cells within the onion’s tissues rupture when the knife cuts through them, releasing these chemicals into the air.
Tear-inducing chemicals, also known as lacrimogens, are substances that stimulate the lacrimal gland to produce excess tears.
These chemicals can be found in various forms, including gases, liquids, and solids.
Common examples include tear gas, pepper spray, and certain types of spices like chili peppers.
When released into the air or applied directly to the eyes, these chemicals bind to receptors in the eye, triggering an intense lacrimal response.
This leads to excessive tearing, redness, and discomfort.
The Role of Airflow and Knife Speed
Research conducted by scientists at Cornell University has shown that the airflow created during chopping onions plays a crucial role in dispersing these tear-inducing chemicals. When the knife cuts through the onion, it creates a vortex that lifts the droplets into the air. However, if the cut is made too slowly or with a dull blade, the droplets have more time to evaporate before they can be expelled from the body.
On the other hand, cutting onions quickly and using a sharp blade creates a larger airflow vortex, which disperses the droplets more evenly and rapidly into the air. This results in fewer tears being produced by the individual chopping the onion.
Knife speed refers to the rate at which a knife blade moves through the air.
It is typically measured in meters per second (m/s) or feet per second (ft/s).
Various factors influence knife speed, including the type of knife, its weight, and the user's technique.
For example, a lightweight folding knife may have a lower speed than a heavier fixed-blade knife.
The optimal knife speed varies depending on the task, such as cutting paper or slicing through meat.
The A Solution for Chefs
While this discovery may not provide a solution that is suitable for professional chefs, who often rely on their sense of smell to detect even the slightest tear-inducing compounds, it does offer some practical advice for home cooks and individuals who find themselves crying while chopping onions. By using a sharp knife and cutting quickly, you can reduce the amount of tears produced when handling onions.
- newscientist.com | Physicists reveal the secret to chopping onions without crying
