Why does onion make you tear up?

In this brief guide, we will answer the query, “Why does onion make you tear up?” We will also discuss the different ways to prevent getting teary-eyed while cutting onions and the tips to reduce tears while cutting onions.

Why does onion make you tear up?

Onion makes you tear up because when you chop an onion, you break open the cells of onions, and certain (lachrymator) chemicals like Propanethial S-oxide are produced, irritating the nerves surrounding the eyes (lacrimal glands).

These molecules are made up of the amino acid family’s methionine and cystine. These chemicals are released into the air when you cut an onion. When this happens, an “enzyme” transforms the amino acids into lachrymator chemicals. Sulfuric acid in this form irritates the nerves around the eyes, causing them to tear.

This is actually a defense mechanism to protect the onions from any kind of attacks from different organisms under the soil as they grow. When any animal attacks the onions damaging the skin of an onion, enzymes and sulfenic acid are released as a countermeasure. When these chemicals react, they form propanethial S-oxide releasing irritant tear gas.

How can we prevent getting teary-eyed while cutting onions?

Try the following steps to prevent getting teary-eyed while cutting onions:

Cut the onions properly

The way you cut the onions also determines the effect it has. Firstly, you should always use a sharp knife while cutting onions, so that you can get it done quickly with the least amount of damage to the onion cells. After all, the chemicals that cause you to tear up are released when the onion cells get damaged. The lesser the damage, the lesser irritants are released in the air.

It is better to cut the onion away from you so that the onion vapor does not enter your eyes directly. Also, it’s best to avoid cutting your onion at the root end, regardless of how you slice it. Since this area has the highest sulfur concentration, it can make you tear up.

Use water

Soaking the onions in water for at least 30 minutes before you cut the onions is the best way to dissolve the amino acids or reduce the sulfuric acid molecules in onions. 

This will help to reduce the effects of these tear-causing chemicals to some extent. It is more effective if you cut the onions into medium sizes before soaking them in water. Just make sure that the onions are dry before you throw them in the hot oil.

Freeze the onions 

Freezing the onions before cutting them can also reduce the effects of tear-causing chemicals to some extent. When you expose the onions to low temperatures, you can suppress the scattering of the lachrymator chemicals. When you cut the onions at room temperature, the onion vapors will not spread as far as when you cut them without freezing.

Protect yourself from onion vapors

You can get help from various equipment while cutting the onions to protect yourself from these onion vapors. You can use goggles to protect your eyes from harmful chemical secretions. 

You can also use a fan to blow the chemicals as far away from you. Cutting the onions under a ventilated area is also said to be useful. It is also believed that keeping a slice of white bread in your mouth helps to collect onion vapor minimizing the effects of tear-causing chemicals.

What are the tips to reduce tears while cutting an onion?

Tears flowing from your eyes while cutting the onions can be annoying and inconvenient at times. Although you can’t avoid this natural phenomenon, here are some suggestions to help you to reduce tears while cutting onions:

  • Try to put a barrier or gap between you and the raw onion when you’re cutting them. You can place the cut onions behind glass or extend your desk.
  • Cool, clean water should be used to rinse your eyes if you get teary.
  • To relieve inflammation, place a cool washcloth or cool cucumbers over your eyes.
  • To flush out the eyes, use lubricating eye drops.
  • Other sore eye cures include cotton balls soaked in aloe vera gel and water, as well as sterile castor oil eye drops.

Conclusion 

In this brief guide, we have answered the query, “Why does onion make you tear up?” We have also discussed the different ways to prevent getting teary-eyed while cutting onions and the tips to reduce tears while cutting onions.

Citations 

https://www.britannica.com/story/why-do-onions-make-you-cry

https://www.healthline.com/health/why-do-onions-make-you-cry

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