What is it about cooking with onions that brings tears to our eyes?
I’ve done a lot of cooking in my day, and I was determined to learn the reasons for this, as well as how to combat them in my own kitchen.
Read on for a quick explanation of the chemistry involved in the process, my methods for deducing the best tear-free chopping techniques, and my top five tips for prepping onions without crying.
Chemistry that Makes You Cry
According to Everyday Mysteries from the Library of Congress, when it comes to the chemical composition of onions, we know that they produce a chemical compound called syn-propanethial-S-oxide. Cutting an onion releases this gas.
When it wafts up towards your eyes, it bonds with their natural moistness, creating sulfuric acid. And sulfuric acid burns.
Hence, we cry.
Seeking Sweet Relief
I went about my research very unscientifically, by asking other chefs, family, and friends for their best tips.
And let’s not forget the many lovely church ladies in my small Gulf Coast hometown – they had plenty of advice to share as well.
Why did I focus on gathering anecdotal evidence from these individuals? Because they’re the best cooks I know!
Examining the Evidence
What did I learn in my research? A lot, some good, some bad.
Let me fist dispel some myths: I was told to burn a wooden match, blow it out, then hold it between my teeth and breathe through my nose as I sliced. Or to bite a toothpick, place an ice cube in my mouth, or chew gum while I chopped.
I’m just not that coordinated!
I was also told to keep a lit candle near the cutting board, run a small fan to blow away the gases, and run cold water in the sink while I sliced the vegetables.
I think my favorite idea came from a neighbor, who always cuts her onions on the front porch so she can visit with neighbors as she works.
I imagined my neighbors leaving my house, their eyes streaming with tears, and decided I’d rather not try this method.
Chef-Centric Test Run
Next, I bought ten pounds of onions and commenced to chopping.
As the result of what I must say was a valiant effort, after dicing and slicing many onions, and two full boxes of tissues later, I am sorry to say none of these ideas worked well for me.
So, I decided to turn instead to methods that have actually proven to be useful for many experienced chefs and cooks.
The Bottom Line – How to Stop the Tears
Take a look at the top five winning tips, for the best ways to steer clear of onion tears:
1. Your Refrigerator or Freezer is Your Friend
It turns out that placing an onion in the freezer (for a quick 10 minutes) or refrigerator (for just 30 minutes before cutting) works. It keeps the cells from “exploding” into the air as quickly as a room temp onion can.
2. A Stovetop Ventilation Fan Can Work Wonders
Try placing your cutting board securely onto your front stovetop burner. Make certain it is off and cool first, and turn your hood or ventilation fan on high. It helps to redirect the gases away from your eyes.
3. Don’t Cut the Root End
Seriously, here is where we get to the root of the problem. Chefs will tell you that the tear-jerking sulfur compounds are concentrated here. Once you cut into the root, they billow into the air – and your eyes.
4. Always Use a Sharp Knife
It’s well worth investing in a good knife sharpener and honing steel to keep your knives safe, and more efficient to use. The sharper the knife, the less you will smash the cells of the onion, or tear up. Sharp knives make your work safer, quicker, and easier.
5. Try Onion Goggles
Yes, there is such a thing. These eye-saving gadgets prevent noxious fumes and gases from getting near your eyes. A wide variety of styles and colors are available on Amazon.
If you are an eyeglass wearer, try chemistry goggles instead, to enjoy the same benefits – they’ll fit right over your glasses.
Sometimes the best cooking tips come from food scientists, while other times they’ll originate with your family, neighbors, or even your friendly resident food blogger. But the real test comes from you.
Whatever method works for you is always going to be the best, right?
I can’t wait to hear all about your best onion cutting tips, and how these work for you, too! Share with me in the comments below.
Photo credits: Shutterstock. ORLBUE product photo courtesy of ORBLUE.
About Marla Tetsuka
As a professional chef, author of multiple cookbooks, and graduate of the esteemed Le Cordon Bleu College of Culinary Arts, Marla brings a professional touch to the community that we call Foodal.