New Year's Resolution - No More Tears

Photo from the US National Onion Association

The onion - allium cepa - has been a staple part of almost every cuisine in the world throughout almost all periods of history. Ancient Greek athletes consumed onions for strength, the Roman philosopher Pliny the Elder prescribed them as a cure for toothache and dysentery, the Pilgrim Fathers took onions with them to the New World only to discover that the Native Americans already consumed them in huge quantities and Queen Elizabeth I used the plants (somewhat unsuccessfully) to clean and strengthen her teeth.

I was brought up with the adage that all cooking starts with onion and garlic - only once they are sweating off do you decide what to cook. So - the perfect culinary product, except for one thing... yes... boo hoo...It's tears time! Those readers with an interest in fokelore aspects of kitchen practice may be familiar with sucking on white bread, wearing spectacles, chewing gum, freezing the onion, putting a wooden spatula in the mouth, using a very sharp knife, chopping close to running water, breathing through the mouth, chewing parsley, lighting a candle nearby...

Most of these approaches will help, but none are necessary if you understand the science behind the tears. The experienced chefs amongst you will already know how to protect your eyes while chopping onions. For everyone else, here's the science. When onions are sliced the individual cells are broken open. Onion cells have two sections - one with enzymes called alliinases, the other with sulphides. Although some exzymes are found throughout the bulb, the root section contains far more than the upper part of the bulb. When the root section is chopped roughly or crushed, the enzymes are released to break down the sulphides and generate sulphenic acids which then decompose into the volatile gas syn-propanethial-s-oxide. If this gas reaches your eyes it reacts with water to form dilute sulphuric acid. This irritates the nerve endings in the eyes, making them sting and causing the tear glands to produce tears in order to dilute and flush out the irritant.

Now you can understand how the folk remedies work. They rely on destroying the gas by heating, reducing its production by cooling, absorbing it directly in the mouth and protecting the eyes. But here's how the pros do it. I can't claim to be a world expert, but I certainly don't suffer from onion tears. If you are going to try this yourself, make sure your knife is as sharp as you can get it and be careful not to chop your finger tips off in the process. After all, tears are just a temporary inconvenience.

Sorry about the bleary-eyed look. It was due to a very late night seeing in the New Year at Canary Wharf last night, rather than anything to do with syn-propanethial-s-oxide. As for the red onion suddenly transforming itself into a Spanish onion - so you don't even pay to see the video and you expect professional continuity?

O neste vídeo eu mostro o método usado por um chef da cozinha cortar uma cebola sem água nos olhos.