Mmm…Savory, delicious onions. Fried, grilled, or caramelized, they add so much flavor to your dishes. How you love them so. If only they didn’t make you cry.
If you understand why you cry when you cut onions, methods for avoiding the problem become more clear. Onions cause tears due to a chemical reaction. This reaction occurs when you cut and damage the onion’s cells. This chemical reaction proceeds in the following manner. First, when you cut an onion, lachrymatory-factor (LF) synthase is discharged into the air. The synthase enzyme transforms the onion’s amino acid sulfoxides into sulfenic acid. The sulfenic acid becomes syn-Propanethial-S-oxide. Finally, the syn-Propanethial-S-oxide floats into the air and gets into your eyes. This irritates your eyes’ lacrimal glands which cause the tears to flow. Ah, but your love affair with onions does not have to end in sobs. Here are five tear-free methods for cutting onions.
1. Use a sharp knife
It’s best to use a sharp knife when cutting onions. A sharp knife slices more easily through the onion causing less damage to the onion cells. It requires a bit of force to slice a dull knife through an onion, which severely damages its cells. Once the onion cells are damaged, noxious gases are released into the air, causing your eyes to sting and tear up. When you forcefully lunge a dull knife into an onion, instead of effortlessly gliding a sharp knife through the vegetable, you expel additional amounts of the LF chemical into the air.
2. Chill the onions
Chilled onions are less likely to make you weep while cutting them. Chilling onions before slicing into them slows the chemical reaction that occurs when they are cut. In fact, it decelerates the amount of propanethial S-oxide that is expelled into the air when you cut onions. This means fewer tears. To properly chill onions, place them in the refrigerator for a half to a full hour prior to cutting them. If you are short on time, you can place them in the freezer for approximately 20 to 30 minutes before use. Do not let your onions become completely frozen as that will make them too hard to cut.
3. Turn on a fan
It has already been established that the reason slicing an onion causes tears is because of the irritating gases released into the air while doing it. Therefore it makes sense that one way to eliminate the tears would be to just blow the irritating gases away from your eyes. If your stove hood has a fan, place the cutting board on your stovetop and allow the hood fan to suck the gases away from you. If your stove lacks this feature, any table fan will do.
4. Vinegar or lemon juice on the knife blade
A little vinegar or lemon juice on your knife blade will counteract the irritating compounds that form during the chemical reaction caused by the broken cells. You should be aware that this method, while effective, will leave your onions with a slight vinegar or lemon taste. This can change the flavor of some recipes. You should only use this trick if you do not mind a slight change in flavor.
5. Put your goggles on
Of course, the best way to refrain from crying while chopping those onions is to properly cover and protect your eyes throughout the task. On that note, put on a pair of goggles. If you like, you can get a special pair of goggles that are made specifically for cutting onions. However, ordinary swimming goggles will work. Goggles create a protective barrier around your eyes which prevents the propanethial S-oxide in the air from getting into them.