Onion tears and gardener's secrets

Do onions make you cry when you chop them? Well, unless you've managed to avoid cooking all your life you've probably chopped an onion and experienced that burning, stinging, tears-running-down-both-cheeks thing you get from the onion fumes. Why does that happen? What is there to get all emotional about over an onion?

Apparently when you cut an onion, you break the onion cells and release their contents. When you slice the onion flesh amino acid sulfoxides form sulfenic acids and enzymes. Up until this point these had been kept separate - but by cutting into the onion it frees them up to mix with the sulfenic acids to produce propanethiol S-oxide, a volatile sulfur compound that wafts upward, and when it hits your eyes it reacts with the water in your tears to form sulfuric acid. The sulfuric acid burns the delicate skin around your eyes and this makes them release their tears, as protection, washing away the irritant as you cry and sob.

So, you are literally crying acid tears!

Just look at these onions, the wine bottle is to give an idea of scale (honestly), they must contain enough enzymes to make gallons of tears. They probably contain enough acid inducing chemicals to make vast armies cry oceans of sulphuric acid tears. They were given to me by a neighbour of mine; he grew them on his allotment. They have to be three of the biggest onions I have ever seen outside of a county show and even then I think these may be bigger. Chris tells me - Chris is my neighbour’s name - that compared to some of the onions he has grown that these are pretty small! What is he putting into his soil I wonder – elephant dung! When I asked him how he’d managed to grow these whoppers he simply smiled and with a twinkle in his eye said that he didn’t know. Didn’t know?

That’s the thing with gardeners; they don’t like telling you how they do it, they like their secrets. Acid tears and gardener’s secrets - no matter, either way these are three of the biggest onions I’ve ever seen and I’m sure that you’d agree that Chris, my neighbour, certainly knows his onions.

Now, I wonder why people say that…