Best ways to avoid crying while cutting onions

Shedding tears or feeling a stinging sensation in your eyes when you cut onions is annoying, isn’t it? 

There are many hacks around this topic, and truly, many of them are just a myth and don’t work.  But knowing why onions make you cry will help you find a way that works for you, maybe not to create a complete tear-free experience depending how sensitive your eyes are, but at least, to make things better.

Why onions make you cray?

Here is a short and easy-to-understand explanation. Onions contain sulfur, which they absorb from the soil.  Sulfur is what gives them their pungent flavor. They also contain an enzyme called synthase. As soon as an onion is sliced, those two elements form a chemical compound (called syn-propanethial S-oxide), which is volatile, which means that when it is released, it quickly evaporates in the form of a gas.  When this gas is released into the air, it can trigger and irritate the lacrimal glands in the eyes, causing them to water, and when this happens,  you start shedding tears.  

What can you do?

In general, there are two important things to help minimize crying when cutting onions.  The first one is to reduce the amount of gas that is released when cutting them and the second one is to keep as much gas as possible from coming in contact with the eyes. 

So here are some suggestions that works well to accomplish those 2 goals:

a. Use a good sharp knife.

A sharp knife will make a cleaner and better cut in the onion and will ‘damage’ the skin the least.  Doing as little damage to the onion as possible when you cut it, will help reduce the amount of gas released. A dull knife will not create clean cuts, but will crush the flesh of the skin, causing more gas to be released and spread in the air. A good rule of thumb to determine if a knife’s blade is sharp enough or not, is to slice a ripe tomato. If the blade slices cleanly through, the blade is very sharp and the knife will make better and sharper cuts in the onion. Otherwise, it might be best to look for a better knife.

b.. Chill the onion.

Cold onions are supposed to release gas at a slower rate compared to room temperature ones.  Chilling the onion does not affect the taste. Some suggestion here are:

1. Keep your onions in the fridge
2. Pop them in the freezer for 10 or 15 minutes before you cut them
3. Let the onions sit in a bowl of ice water for 30 to 60 minutes before cutting into it.

c. Use cold water.

Some people try to cutting the onion under cold water.  This will not work well when dicing them because the water will push the small onion pieces out of the cutting board and into the sink. However I find that dicing onions right next to running cold water helps, because the water pushes the gas down and this will create less contact with your eyes.  When I do that I collect the water at the bottom of the sink and use it either to water plants or to wash dishes.  That way there is no waste.

For me, using a sharp knife works best, especially if I use a ceramic knife.  

If your eyes are very sensitive, and none of these tricks works well for you, here are a couple of tools that might help you solve the problem:

1. Try some of the goggles that are designed for cutting onions. They cover the area around your eyes to avoid them having contact with the gas released.
2. Use a fan. Cut the onion next to a fan facing the chopping station, pointing to the opposite direction to where you are. This will help blow the gas away before from you decreasing the chance to irritate your eyes.

Share with us how do you avoid having tears when you cut your onions?  Maybe you have a different technique that can help somebody els