Onions are used worldwide to start a vast array of recipes.  While their flavors vary from savory to sweet, they all have one thing in common. They are pungent and strong smelling. This causes most people to tear up when they peel of cut onions.


To understand how to cut onions without crying, it may help to understand the science behind this phenomenon.

Simply put, onions are a root vegetable. As they grow underground, they absorb small amounts sulphur that naturally occurs in the soil.  When mixed with the onion, this morphs into amino acid sulfoxides.  When you cut open the skin of the onion, the amino acid sulfoxides give off that distinct, strong, “oniony” smell.

Your eyes become irritated by this odor.  Why? Because inside your eyelid are glands that cause you to reject things that irritate your eyes. Some examples of these irritants are strong odors, smoke, and pollen. So the “crying” is actually a reflex of the eyes. These tears are meant to protect your eyes.

Now that you understand WHY you cry when you peel or chop onions, let’s look at some easy tricks to help you overcome these tears. Try these 10 easy tricks to cut an onion without tears.


Trick 1: Put On Swimming Goggles

The first trick is the only sure-fire way to prevent tearing up from the onion odor. Wear goggles! Swimming goggles while cooking may sound like silliness. However, it is an easy solution. The goggles form a tight seal around the eyes. Think about it.  If it’s strong enough to keep out water, it will keep out onion fumes. You won’t win any fashion contests with this accessory, but you will prevent onion tears.  Keep a pair tucked away in your kitchen drawer.  Just don’t let your friends see them. They will probably laugh.  Or think you’re a genius.


Trick 2: Use Olive Oil

This second trick involves an item you probably have right on hand in your kitchen–olive oil. Pour a few drops of olive oil onto a paper towel. Then carefully run the blade of your knife along the paper towel. This will coat the blade with olive oil. This works because the molecular weight of the olive oil is heavier than the vapors emitted by the amino acid sulfoxides. Therefore, this helps minimize the rising of the irritants in the onion from rising to near your eyes. Seriously, is there anything that olive oil can’t do?


Trick 3: Cut Your Onion Under Running Water

Most definitely, this is the most common method people use to prevent tears when cutting onions. Turn on the cold water in your sink. Place the onion under the stream of running water while you start to peel your onion.  Literally, this stream of water washes away most of the irritants. One caution. If you are running water while you are peeling and cutting an onion, take precaution to hold the knife securely. The onion is round and becomes slippery. This can cause you to have a slip of the knife and cut your finger.  Be careful!


Trick 4: Sharpen Your Knife Skills

This trick is simple: sharpen your knife. When you are using a sharp knife, you will make clean cuts. This minimizes the smashing effect you end up with when you use a dull knife. This is because when you use that dull knife and smash instead of slicing the onion, you release more of the amino acid sulfoxides.  Therefore, the sharper the knife the less tears you will shed. Your knife set probably came with a sharpener, but perhaps you don’t really know what to do with it. To use the sharpener, run your knife all the way down the sharpener, from the tip of the knife to the hilt (handle). Do this in an away from you motion in case your knife slips off the sharpener. Do this several times in even strokes down the sharpener. You are reshaping the blade of the knife back into a sharp edge.   Wash off any debris and you are ready to cut!


Trick 5: Blow It Off

This may sound silly, but plug in a small tabletop fan.  Point the fan away from you. Turn it on high and let her rip. The fan will mitigate the amount of fumes by blowing them away from you as you cut your onions.


Trick: Start at The Top

This trick involves how you peel your onion. Start at the top! By this, I mean make a clean cut at the top of the onion and only peel it back to about the bottom ¼ of the onion. The sulphur that is absorbed in the soil enters in through the root of the onion. It’s concentrated at the bottom of the onion and continues up through the core. This is why onions are strongest smelling at the bottom and the middle. Therefore, only use the top ¾ of the onion. Then discard the very bottom section since it’s the stinkiest part.


Trick 7: Chill Out

Chill your onion in the freezer for about 15 minutes before you need to peel it. This works very effectively. The cold makes the amino acid sulfoxide molecules slow down. This means that the onion odor will be heavier and not reach your eyes causing that familiar irritation.


Trick 8: White Vinegar Solution

Go back to the pantry for this next trick! Mix 50% white vinegar with 50% filtered water in a food safe spray bottle.  Spritz this onto your chopping board and your knife blade.  The vinegar causes a reaction that snuffs out the onion odor. One note: some cooks swear that the vinegar negatively affects the flavor of their dish.  However, if you are cooking a recipe that contains vinegar you won’t even notice this.


Trick 9: Light a Flame

Many cooks swear by this trick!  Light a flame. Either a gas burner or a candle will work. Cut the onion as close to this flame as you safely can. The flame attracts the amino acid sulfoxide to it. Therefore, it burns off the odor before it wafts us to your eyes causing those tears!


Trick 10: In The Hood

This last trick is so simple it’s almost scary.  Make sure the burners on your range are cool.  Then turn on your exhaust hood. Step back a bit as you peel and chop away, and let your hood pull the onion odors out with the exhaust. 


In conclusion, the tears you shed when you are cutting onions are real. They are a biological process designed to protect your eyes from harm.  These methods work better for some people than others, depending on your particular sensitivity.   Try them out, and you will probably find one that will help you control your tears when you peel onions.