Sometimes when I'm chopping onions I just get all…
TEARY WOW.
WHAT THE HELL'S GOING ON HERE.
When I chop onions it's a constant battle to not feel like I just watched the 1995 classic
A Little Princess.
My eyes well up with tears and it HURTS.
You know?
What's going on?
What is this witchcraft?!
Well, to be honest, you're doing it to yourself.
Your tears reacting with a chemical released by the onion which creates an acid IN your
EYE!!
SO CRAZY.
Okay, so, onions are a delicious root vegetable member of the genus Allium, along with garlic,
leeks, chives, shallots, and some 400 other species,.
When you plant something, it doesn't just suck up water and sunlight; it also needs
nutrients from the soil.
Good soil contains organic matter that the plant can absorb like nitrogen, phosphorous,
carbon, AND sulfur -- which this bulbous fleshy vegetable tends to absorb a lot of!
When you cut open an onion you're breaking apart its cell structure allowing amino acid
sulfoxides to form sulfenic acid.
It also releases the enzyme lachrymatory-factor synthase which reacts with that sulfenic acid
to form an airborne volatile chemical called propanethiol s-oxide.
As that chemical rises into the air it eventually meets the tears already present in your eyes.
There are three types of tears, emotional or psychic tears that we cry when we're sad;
basal tears which are constantly replenished to keep our eyes lubricated; and reflexive
tears which flush the eye in response to an irritant -- like ACID.
Tears contain water, mucus, oil, nutrients for eye cells, and antibacterial lysozymes.
When propanethiol s-oxide hits that water, it rearranges YET AGAIN, forming sulfuric
acid -- battery acid!
IN YOUR EYES!
So, you cry when an onion is cut because enzymes create battery acid in your eyes.
Just another day for nature.
The more I learn about the world, the less I feel like I actually know about anything.
I know what you're thinking, "Why don't we just breed this nightmare ingredient out of
onions?!
We can make seedless fruit, why not tearless onion?
Well, you can refrigerate the onion to slow down the chemical reaction and reduce crying,
but getting rid of it altogether would involve breeding it out, and previous studies of onion
biology concluded the onion's flavor AND the acid reaction was thought to come, in part,
from the enzyme alliinase.
Breed out the alliinase and the onion wouldn't taste like… well… an onion.
Then in 2002, a study in Nature found that may not be true at all!
Instead, they believe there's a quote "yet undiscovered enzyme," at work here.
That's right.
Onions are confounding science.
to Maybe we could breed onions that have less of that mystery enzyme, maintain the flavor
and not get red and puffy, but we don't
know yet.