Are you tired of crying every time you peel and cut onions? We have the solution, and it’s not wearing a diving mask.
Cutting an onion, many of us have experienced the tears that flow involuntarily. This ingredient is part of many recipes, but cutting it can be a real ordeal, even for professional cooks, so much so that sometimes we remove it from the recipe to avoid the fit of tears. The explanation: underground, the onion absorbs the sulfur present in the soil, and when it is cut, a chemical reaction occurs creating sulfenic acid, itself transformed into propanethial oxide. It’s this gas that makes us cry.
This is a common reaction and yet there is a trick that seems to defy this phenomenon. This often-shared tip involves putting the onion in the refrigerator or freezer before cutting it. But is this just a cooking myth or is there real science behind this practice?
How can simply cooling an onion help reduce the tear reaction? The answer lies in chemical kinetics. By lowering the temperature of the onion, the enzymatic reaction responsible for the formation of sulfur compounds is slowed down. This means that once you cut the cold onion, less tear gas is released into the air, reducing stimulation of the tear glands and therefore tear production.
All you have to do is place your onions in the freezer for 10 minutes or 30 minutes in the fridge before starting your recipe. You can also place them in a bowl of cold water for 30 minutes. Onions don’t like the cold, this prevents them from releasing their gas and limits the watery effect. You can cook in complete peace of mind. If you didn’t get it done in time, all is not lost, there are also other methods to reduce tears while cutting onions.
While some recommend wearing protective glasses to prevent gases from coming into contact with the eyes, we advise you to try the lemon or piece of bread trick instead. The first is to simply squeeze a lemon and dip the knife blade in it before moving on to cutting your onion. The acidity of the lemon will help limit the transmission of gas emitted by the onion, and thus reduce tears.
The second is an unusual grandmother’s method. This would involve holding a piece of bread between your teeth to absorb the irritating gases. Simply keeping your mouth open would protect the tear glands from gases that would be attracted to saliva and less to the eyes.