Tears We Cry

The Tears We Cry

“An onion can make people cry,
but there’s never been a vegetable that can make people laugh.”
~ Will Rogers

Plants are essential to life. While not all plants may appeal to humans, they are nutritious and tasty to various forms of animal life.

Will “A stranger is a friend I haven’t made yet” Rogers

Unlike antelopes or rabbits, plants can’t run away or physically fight back, like wasps and badgers, when threatened. To survive and reproduce, most have developed defense mechanisms to deter animals and fungi from consuming them.  ^[1]

Some have thorns.  Some others release bitter tasting chemicals, or foul smells when disturbed.  Some even emit pheromones to confuse their predators.

Onions are a particularly popular human food. They emit an inviting aroma when sautéed or baked and complement many dishes, from omelets to casseroles to chili. In the United States, onions are the third largest fresh produce industry, with the average American consuming over 18 pounds of onions per year. That’s a substantial amount!

Mmmm. Sautéing onions [I usually chop mine more finely]

However, preparing onions often comes with a tearful challenge. Most varieties make the person cutting them cry, some more than others. As Carl Sandburg put it, “I may cry when I cut an onion, but I also cry when I realize how much flavor it adds to my dish.”

Onions are packed with health benefits, including antioxidants, vitamins C and B6, and other natural compounds that help control blood pressure, promote heart health, aid digestion with fiber, and contain cancer-fighting sulfides and polysulfides. Additionally, thiosulfates in onions can inhibit the growth of microorganisms and help prevent blood clots

Growing underground, onion bulbs are tempting treats for small animals like voles and mice, though not squirrels, which dislike their smell and taste. This aversion is fortunate since onions can damage a squirrel’s blood cells and cause anemia.

Onions evolved a defense mechanism with special enzymes and sulfenic acids that activate when their skin and layers are broken. These compounds produce propanethial S-oxide, a gas released into the air. When this gas contacts water, such as the moisture on our eyes, it forms sulfurous acid – a potent irritant in organic chemistry.  It’s almost identical to sulfuric acid (H₂SO₃ vs H₂SO₄, but not as corrosive).

Our eyes are coated with a water and oil layer for lubrication. Tiny droplets of sulfurous acid form on account of the cornea’s water layer.  Our eyes sense this and release additional water (reflex tears) to flush out the irritation.

Note from experience.  Onion juice also contains the same compounds; water from the air, your hands and your eyes will produce an advanced effect! During and after slicing, dicing or cutting an onion: NOT rub your eyes until after thoroughly washing your hands! Or touch anything, as you can’t be sure who will touch that surface next.

So, how can you minimize the tears when slicing onions (and their relatives, like scallions, leeks, and green onions)? Here are a few tips:

• Use a fan to disperse the gas.
• Cut the onion underwater, such as in a large pot or on a cutting board in the sink. The water traps the gas, then dilutes the sulfurous acid.
• Wear goggles for protection.
• Chill the onion before cutting. This slows the enzyme reactions. I’ve inadvertently discovered this when storing a leftover onion in the refrigerator; the next time I cut it, the effect is milder.
  

  Sophia Lauren, through the decades

“If you haven’t cried, your eyes can’t be beautiful.” – Sophia Loren

Whether it’s a wee dash of sulfurous acid or an emotional jolt, these are real and valid reasons to cry.  Be not ashamed.

Joe Girard © 2024

Thank you for reading. As always, you can add yourself to the notification list for newly published material by clicking here . Or emailing joe@girardmeister.com

[1] many plant “fruits” are actually designed to attract and be eaten by animals – this helps spread their seed.

Final Thoughts:
The full chemical process as I understand it.

• Cut an onion and its cells release alliinase, and enzyme that converts its amino acids into sulfenic acids.
• These acids are unstable; the molecules re-arrange to form propanethial S-oxide, an invidible gas containing sulfur and sulfur compounds.
• When this gas contacts water, like on the cornea, It reacts to form a sulfurous acid.
• Sulfurous acid is very reactive with many chemicals, especially all animal tissue.

BTW: Sulfuric acid’s pH is near 1.0.  Sulfurous is 1.5.

Although the S-oxide gas is quite a bit heavier than air, it still reaches the face.  General wafting caused by air motion.  On account of diffusion due to partial pressures, the gas will tend to migrate from higher concentrations to lower concentrations.

I put in squirrels as they are rodents, like voles and mice.  And capable of reaching onion bulbs.