Cutting onions can be a painful experience for the eyes and tear ducts. The sulfuric compounds in onions are irritants that are released into the air when the onion’s cells are damaged during cutting. This causes a stinging, burning sensation in the eyes that results in tears streaming down the face. However, there are ways to avoid or minimize this reaction when prepping onions. With a few simple preparation tricks and techniques, you can cut onions without sobbing over the cutting board.
Why Do Onions Make You Cry?
Onions contain amino acid sulfoxides, which form propanethial S-oxide when an onion’s cells are damaged. Propanethial S-oxide evaporates and travels towards your eyes, where it gets converted into sulfuric acid upon contact with the water in your tears. This creates a stinging, burning sensation.
The more onion cells that are ruptured, the more propanethial S-oxide is released. So slicing or chopping an onion tends to create more irritation than keeping the onion whole or cutting it in half. Damaging more cells also creates more tears.
Cutting Onion Hacks to Prevent Tears
Here are some tips and tricks to cut an onion without crying:
Chill the Onion
Place the onion in the freezer for 15-30 minutes before cutting. This helps slow down the chemical reaction that produces the irritant gas. A chilled onion means fewer sulfur compounds released and less irritation. Make sure the onion is dry before cutting.
Use a Super Sharp Knife
A sharp knife glides cleanly through the onion, damaging fewer cells in the process. This minimizes the release of sulfur compounds. Dull knives crush and tear more onion flesh, creating more irritants. So invest in quality, sharp knives and keep them honed.
Cut Off the Root End Last
The root end of the onion has the highest concentration of sulfuric compounds. Leaving the root end intact for as long as possible reduces exposure to the gases during prep. Cut off the stem end first, peel the onion, and slice from the top down leaving the root end for last.
Cut Under Running Water
Cutting the onion under a gentle stream of water helps rinse away the irritant gas before it reaches your eyes. This dilutes the concentration of propanethial S-oxide in the air. Just take care with your knife grip since water makes surfaces more slippery.
Use a Fan
Position a fan next to your cutting board to blow the onion gas away from your face as you slice. Make sure the fan is off to the side and not directly in front of you, so it doesn’t blow the gases directly into your eyes.
Wear Eye Protection
Safety goggles form a barrier against the onion vapors from reaching your eyes. Swimming goggles or ski goggles work well since they have a tight seal. You can also buy specialty onion goggles that have ventilation slits. These allow you to see while blocking irritants.
Cut Away from Your Face
Don’t lean over the onion as you slice it. Keep your face back from the cutting board to prevent the fumes from wafting upwards directly into your eyes. Cut away from yourself, keeping the onion further from your face.
Use a Vegetable Chopper
Devices like the slap chopper or food processor chop all the onion at once, avoiding prolonged exposure to the vapors. They also keep your eyes further away compared to hand chopping on a cutting board. Just be sure to pulse rather than continuously run the motor to prevent over-chopping.
Light a Candle
Lighting a candle or gas burner near your cutting board helps burn up some of the propanethial S-oxide before it reaches your eyes. Be cautious of fire safety when working next to an open flame.
Rinse Your Eyes
Keep an eye wash solution handy while prepping onions. Some homemade options are saline solution, diluted vinegar, aloe vera juice, or vegetable oil. Rinse your eyes occasionally as needed to wash away irritants and refresh.
Avoid Rubbing Your Eyes
It’s natural to want to rub your eyes when they sting. But don’t do it! Rubbing will push the onion juices from your hands into your eyes, making the irritation worse. Rinse your hands after handling onions so you don’t accidentally touch your eyes.
Alternative Onion Cutting Techniques
Certain cutting styles create less exposure to onion vapors:
Dice It
Dicing the onion into small pieces minimizes the exposed surface area. With less cut onion flesh exposed to air, fewer irritating sulfur compounds are released.
Slice the Root End Last
As mentioned earlier, leave the root end intact for as long as possible when slicing an onion. Only cut through the root end once you’ve sliced the rest of the onion.
Cut in Half, Then Slice
Cut the onion in half from root to stem end first. This exposes less interior onion flesh. Then lay each half flat side down and slice from the top.
Use a Mandoline
A mandoline uniformity and quickly slices the onion with a safe handguard protecting your fingers. The speed means less exposure time to the vapors.
What About Chemical Sprays and Gadgets?
You may have heard of anti-tear sprays, gadgets, or contraptions that supposedly reduce crying when cutting onions. Do these remedies really work?
Onion Goggles or Screens
As mentioned earlier, vented onion goggles provide a protective barrier for your eyes. Screens that attach to your cutting board function similarly by blocking vapors. These accessories do offer some reduction in irritation.
Onion Salt
This product claims that sprinkling it on freshly cut onions neutralizes the sulfur compounds. However, scientific testing shows onion salt is not effective at preventing tears. Don’t waste your money.
Freeze or Chill Onions
Simply chilling onions before slicing is an effective tear-reduction method. But specialty plastic gadgets designed to chill onions have not proven more useful than putting onions in the refrigerator or freezer.
Lighted Chopper Gadgets
Various “As Seen on TV” choppers have built-in lights that supposedly destroy the tear-inducing enzyme. Unfortunately, scientific data does not confirm these devices make cutting onions less lachrymatory.
Anti-Tear Sprays
Sprays made from oil, lemon juice, onion extract, or other compounds can create a barrier to temporarily block sulfur compounds. However, they often aren’t very effective and need frequent reapplication.
Conclusion
With the right techniques, cutting an onion doesn’t have to end in tears. Using a sharp knife, chilling onions beforehand, protecting your eyes, cutting in certain styles, and working quickly can help minimize irritation. While anti-tear gadgets and sprays aren’t totally useless, simple tricks like rinsing your eyes work just as well or better. Remember to take precautions, work smart, and you can chop onions tear-free.
