Of all the kitchen nightmares the cook has to live with, the one that generates the most problems for many is the peeling and chopping of onions, and the associated tears and stinging eyes.
The reason why it makes you cry is because the synthase enzyme converts the amino acids sulfoxides of the onion into sulfenic acid. The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide. Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes. The lachrymal glands become irritated and produces the tears!
Did you get all that, because I just looked it up, and don’t understand a word! To put it simply, chopping onions causes the release of an irritant gas in the air which, when it reaches your eyes, triggers a blinking and tearing reflex designed to wash it away (why didn’t they just say that?)
Not all onions are created equal. The fresher the onion, the less you cry. And not all cooks are sensitive to this phenomenon. Most tips are designed to either hinder the release of the gas, or prevent it from reaching the eyes.
Some people rinse the onions in cold water after peeling, or chop them underwater. Some recommend keeping onions in the fridge, or placing them in the freezer for a few minutes before chopping. Some chop from the stem end down, others from the root end up. Some recommend breathing through the nose, others only through the mouth, while others still hold a sip of water in their mouth, and try not to laugh and spit it out. (Honest, that last one is true).
Some report lachrymal immunity when they wear contacts or chew gum, others suggest putting on lab goggles or a snorkeling mask. Some boast they keep their knives so sharp it’s never a problem, others strive to keep their face well away from the chopping board. Romantics like to keep a lit candle by their chopping board, others opt to simply cry it out.
I’ve only tried a few of these tips myself, but one I hadn’t read about was this intriguing tip, which suggests that you to hold a piece of bread in your mouth as you chop. But it has to be pain au levain. Pain levain is a leavened bread, or sour dough bread. That is to say a mixture of water and flour where a culture of yeast and lactic acid bacteria develops. This fermentation, releases carbon dioxide and allows the dough to rise.
So off I set to the boulangerie because such an unusual tip could not go untested. Using the butt end of the loaf and feeling both experimental and silly, and with a saliva-soaked piece of bread hanging from my mouth, I went about like a mad thing, chopping onnions till my knife went blunt. I’m happy and amazed to report it worked perfectly.
The rationale, I gathered from a little research, may be that the piece of bread absorbs some of the irritant gas before it can reach the eyes. In fact, since trying the pain au levain, I have read that a lump of sugar works just as well. And the fact that you have to concentrate on not drooling on your chopping board may also make this a good hiccup cure! It’s certainly worth a try.
I don’t think I’m going to see this tip demonstrated on TV cooking shows anytime soon, but in my own kitchen, I set the rules of what’s classy and what’s not. (Though maybe I’ll stick with the sugar cube next time!)