Picture this: It’s a cold Saturday afternoon in February. Mike and Sarah are preparing dinner for friends coming over later that evening. Sarah is handling the main course while Mike has been assigned the prep work – chopping vegetables for a hearty winter salad.
“Hey, can you handle these onions?” Sarah asks, sliding a cutting board with three large yellow onions toward Mike.
“Sure thing,” Mike replies confidently, grabbing the chef’s knife.
About thirty seconds later, Sarah glances over and notices tears streaming down Mike’s face.
“Are you okay?” she asks, genuinely concerned.
Mike tries to keep his composure. “I’m fine! It’s just these stupid onions,” he says, wiping his eyes with his sleeve, which only makes things worse.
“You look like you just watched the end of ‘Marley & Me’,” Sarah laughs, handing him a paper towel.
“I swear it’s just the onions!” Mike insists, his eyes now red and watery. “Although… that movie was pretty sad.”
As Mike continues battling the onions, he wonders out loud, “Why do these things make us cry anyway? There’s got to be a scientific explanation for this torture.”
And he’s right – there is! Let’s dive into the fascinating science behind why chopping onions turns even the toughest among us into weeping messes.
Table of Contents
Why Do We Cry, Anyway?
Before we dive into the onion mystery, let’s ask ourselves: why do we cry in the first place? What’s the biological process that triggers our eyes to release tears?
The truth is, tears form for several reasons. The first reason is emotional – whether negative emotions like sadness, anger, fear, or even hunger, or positive emotions like happiness and intense joy. Both types ultimately stimulate tear production.
Some thinkers believe that emotional tears, which contain high levels of stress hormones and other chemicals, ultimately work as a natural painkiller for the body, similar to endorphins. So when someone says, “Go ahead and cry, you’ll feel better,” they’re not just making that up – there’s actual science behind it!
The second reason for tear production lies in what we call basal tears. These are the tiny amounts of tears constantly present in our eyes to protect the cornea, clean the eye, and keep it moisturized all the time.
But the type of tears we’re interested in today is involuntary tears – tears that are automatically released when inflammation occurs in the eye or when something gets into it. The eye immediately begins secreting tears, not just to wash and moisturize but also to deliver antibodies that kill bacteria and overcome harmful substances.
Basically, your eye uses tears as a defensive mechanism against intruders. Think about when an annoying mosquito flies toward you, ignores the rest of your body, and viciously aims straight for your eye, causing complete chaos. Your eye starts producing tears in large quantities, partly to recover from the disruption the mosquito caused and also to sterilize the eye. It’s also trying to use tears to expel the mosquito itself.
Or remember when you’re sitting at your desk writing something, and suddenly, with one reckless move, you wave a paper around and – bam! – it hits you in the eye, creating one of the most dramatic desk-related injuries in history. Again, your eye starts releasing a flood of tears to address the disaster you’ve created.
The Essential Onion
Let’s get back to onions. Truth is, they’re one of the most fundamental ingredients in cooking across America and around the world. Onions are the backbone of countless recipes, from soups and stews to salads and sauces. They’re so essential that the average American consumes about 20 pounds of onions per year!
From home kitchens to professional restaurants, onions find their way into virtually everything. That pot of chili simmering on your stove? Onions. That burger from your favorite fast-food joint? Onions. That fancy risotto at the expensive Italian restaurant? You guessed it – onions.
Even professional chefs who’ve been cooking for decades still tear up when cutting onions. From the short-order cook at your local diner to celebrity chefs on TV cooking shows, you’ll catch them all wiping away tears while chopping onions. The strange thing is, despite the waterworks, they keep coming back to this tear-inducing vegetable day after day, fully aware of the weepy consequences!
Why Do Onions Make Us Cry?
The real reason we cry while cutting onions actually lies within the onion itself. The moment you cut into it or try to chop it, you’ll immediately find a volatile substance approaching your eyes called syn-propanethial-S-oxide. This compound is responsible for everything – it’s what causes the skirmish with your eyes that leads to tears.
What’s fascinating is that this substance isn’t actually present inside the onion to begin with. There’s a “factory” inside the onion that manufactures this compound specifically when it senses that someone with a knife is about to “kill” the onion.
The formation of this compound works like this: inside, the onion contains enzymes called alliinase and amino acid sulfur oxides. The interesting part is that each of these components exists in its own state with no relation to the other – each sits in its own place, not even aware of the other’s existence.
But the moment you bring a knife and start cutting the onion’s cells, these two elements begin to meet and unite for the first time. This creates sulfinic acids that go through a series of reactions until they finally transform into the big boss: syn-propanethial-S-oxide.
Since this is a volatile sulfur compound, it can easily mix with the air and reach your eyes. On the other hand, the cornea of your eye contains sensory nerves that, as soon as they detect this compound, send a distress signal to the nervous system saying, “Help! There’s a major disaster happening here – someone’s cutting onions and we’re all going to go blind!”
The nervous system immediately responds: “Will we ever be done with these onions? Give the order for the eye to close its eyelids so we can be done with this!”
“We can’t, sir. The eye needs to stay open to continue the cutting task that this person is doing.”
“Fine, then, order the nerve fibers in the tear gland area to release some tears to reduce the impact of this disaster and get us out of here.”
And indeed, the eye begins producing large amounts of tears.
The Hidden Bomb in Onions
So ultimately, the idea lies in the internal components of the onion, which is like a time bomb with all its explosive elements present inside but not connected to each other. As soon as the cells are broken, these components begin to interlock, transforming into an armed soldier with a tear gas bomb.
This means you’ll only tear up if you cut or mince the onion. For example, if you peel it from the outside without injuring anything inside, there won’t be any tears or problems. The whole idea revolves around destroying the onion cells from the inside, nothing more.
So if you’re peeling an onion and don’t want to cry, be careful not to damage the onion while peeling it.
Solutions to Prevent Onion Tears
This brings us to another question: is there no solution to this tear problem? Isn’t there a way we can avoid crying while cutting onions?
In reality, there are several solutions:
- Put the onion in the freezer for about 15 minutes before cutting it. Cold temperatures reduce the speed of chemical reactions, so freezing the onion for a short time will significantly decrease the amount of tears. Just don’t leave it in the refrigerator for more than 15 minutes, as its smell will spread throughout the entire fridge, which won’t be pleasant. If your spouse discovers something like that, you might be in trouble!
- Soak the onion in water and cut it while submerged. Get a large pot, fill it with water, put the onion in, and start cutting it while it’s completely immersed. The water won’t give the volatile compound a chance to escape into the air. Of course, if we use this method, we need to be careful because controlling the onion underwater will be much more difficult than outside.
- Light a candle near where you’re cutting the onion. The flame absorbs some of the gas rising from the onion and reduces it.
- Breathe through your mouth instead of your nose as much as possible. This prevents the olfactory nerves from inhaling the gas, which in turn will reduce tears.
- Use special onion goggles. If you want to make things really easy, there’s actually a special type of glasses designed specifically for this purpose that completely protects the eyes from exposure to the gas. Put your glasses on, knife in hand, and go to town on that onion!
And if onions ever make you cry – don’t worry about it. It happens to the best of us!
Final Thoughts
The next time you find yourself at the cutting board with tears streaming down your face, remember that you’re experiencing a sophisticated chemical defense mechanism that evolved over millions of years. Your emotional well-being is perfectly intact—you’re just caught in the crossfire of the onion’s molecular defenses.
Armed with the scientific knowledge about what’s actually happening and these practical solutions, you can now approach onion cutting with confidence. Whether you choose to chill your onions, light a candle, or invest in specialized onion goggles, you’re now equipped to handle this kitchen challenge like a pro.
So there you have it – the molecular drama behind those onion-induced tears. Next time you’re chopping away in the kitchen and feel the waterworks coming on, you’ll know exactly what chemical warfare the onion is waging against your eyes. And more importantly, you’ll have a few tricks up your sleeve to fight back!
