Cutting Onions and Burning My Eyes

Cutting onions doesn't have to bring tears to your eyes.

Cutting onions can sting your eyes. There are several things you can do to prevent onions from releasing their stinging vapor and prevent the vapor from reaching your eyes.

Cause

When you cut into an onion, it releases a vapor containing a chemical compound called propanethial-s-oxide. The vapor converts to sulfuric acid when it reaches the eye, causing tears and stinging.

Temperature

The chemical compounds that burn the eyes become volatile at temperatures above 50 degrees. Chill onions thoroughly before cutting into them to avoid stinging vapors.

Roots

Most of the compounds that cause stinging are in the base or root end of an onion. Keep the root end of the onion intact while cutting the onion.

Tear-Free Tips

Cut onions in a well-ventilated room using a sharp knife. A candle burning near the cutting board will draw the stinging fumes toward the flame. White vinegar on the cutting board may also help prevent fumes from reaching your eyes.

References

• University of Nebraska Extension: Cooking With Onions Without Crying
• Mother Earth News: Pick the Perfect Onions