chemical in onions causing tears


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chemical in onions causing tears

The cause of tear-inducing onions has been discovered! It’s a chemical called syn-propanethial-S-oxide (C3H6OS). Cutting or damaging an onion triggers this compound to contact our eyes and create a burning sensation. That then activates the tear glands.

This compound only exists in onions and very similar vegetables, like garlic and shallots. This explains why we don’t cry when slicing up other fruits and veggies.

If you want to avoid tears while chopping onions, a few options exist. Cooling the onion in the refrigerator is one way. The cold slows down the chemical’s release, toning it down. Cutting underwater or next to running water is another strategy. The water dilutes and washes away the compound before it reaches your eyes. Wearing goggles and using a fan are also useful.

Researching why onions make us cry could lead to solutions that stop tears from happening. In the meantime, these ideas can reduce discomfort while cooking.

What causes tears when cutting onions?

Have you ever pondered why onions make us cry? The answer lies in syn-Propanethial-S-oxide – a volatile compound released when an onion is cut or crushed. It’s an onion’s defense against predators.

When you slice into an onion, the cells are damaged and enzymes break down amino acid sulfoxides. This forms syn-Propanethial-S-oxide vapor that easily enters our eyes. It reacts with the moisture present, producing sulfuric acid which irritates the nerves causing tears.

Not all onions make us cry equally. Varieties with higher sulfur compounds are more tear-inducing. Refrigerating before cutting can reduce the chemicals’ volatility.

The National Onion Association found that cutting horizontal slices minimizes tears as fewer cells are damaged.

So next time you’re teary-eyed in the kitchen, thank syn-Propanethial-S-oxide for protecting those onions!

The chemical responsible for tears

Onions, adding flavor and depth to dishes, have a secret weapon: making us cry! It’s caused by a chemical compound called syn-propanethial-S-oxide. This is released when onions are sliced or cut. It then reacts with the air, forming sulfuric acid and irritating our eyes. So, our body’s defense mechanism kicks in with tears.

Different types of onions contain this chemical in different amounts. For instance, yellow onions have more than sweet onions or red onions. Cooking reduces the potency, but doesn’t eliminate it.

To minimize tears, chill the onion before cutting. This slows down the release of syn-propanethial-S-oxide. Also, try breathing through your mouth while slicing – this helps prevent the compound from reaching your eyes.

How does the chemical affect the eyes?

Onions contain a special chemical. When we cut into the layers, syn-propanethial-S-oxide is released. This compound irritates the nerves in our eyes, so they produce tears as a defense.

Tiny droplets of this chemical float through the air and reach our eyes. Our tear glands respond by making tears to get rid of the irritant. This chemical isn’t bad for our eyes; it just makes them respond. The amount of tears varies between people.

To reduce the amount of tears while preparing onions, there are some solutions. Put the onion in the fridge for 30 minutes before cutting. Wearing goggles or using an onion-chopper can also help.

The next time you’re tearing up while cutting onions, remember that your body is just trying to protect itself. Experiment with different techniques and don’t let teary eyes stop you from enjoying the flavors of onions!

Other effects of the chemical

Onions are infamous for making tears, but there’s more to this chemical than that! From physical to emotional, the effects can range in intensity. Let’s explore these further.

Eye Irritation is the most common; it leads to tearing and unease. Nasal Congestion is also brought on by the chemical. And, last but not least, an emotional response! It could be feeling overwhelmed or moved.

Not everyone has the same reaction to this chemical. Some may only experience mild discomfort, others might be more affected emotionally. Make sure to be aware of the unique effects onions can have! Be prepared for unexpected reactions when dealing with them in your life. Knowledge is power!

Research on reducing tears when cutting onions

Research has been done to find ways to cut onions without tears. Here’s some key findings:

  • An enzyme released when we cut onions causes eye irritation.
  • Placing a running faucet near you can help reduce tear production.
  • Chilling the onion slows the release of irritant gases.
  • Using a sharp knife minimizes crying.
  • Goggles or a slice of bread in your mouth also helps.

Did you know that cutting onions under cold water can reduce tears? This washes away the irritant gases before they reach your eyes. By using these techniques, you’ll have a tear-free onion-cutting experience!

Pro Tip: To avoid tears, freeze the onion for 15 minutes before slicing. The cold temperature reduces the irritant compounds and makes chopping more pleasant.

Techniques to minimize tears when handling onions

Chilling onions before cutting them can help stop tears. Here’s a 5-step guide!

  1. Put it in the fridge for 30 minutes. Cold temp prevents the gas from coming out.
  2. Keep your knife sharp. A dull blade will cause more damage and release the tear-inducing compounds.
  3. Create a water shield. Put a bowl of water nearby to absorb the gas.
  4. Slice vertically, from root to stem. This will contain the chemicals in each cut section.
  5. Work with proper ventilation, like an open window or a fan. This helps disperse the irritants.

Soaking the onions in cold water or chewing gum can also help.

Did you know that onions have been around for over 7,000 years? Ancient Egyptians believed eating them could give strength and protect from evil spirits! So the next time you cry over cutting onions, remember their history.


It’s obvious that the tears caused by cutting onions are due to a chemical compound found inside the veggie! This solves the mystery of why our eyes get watery and sore when we chop onions.

The main culprit is syn-propanethial-S-oxide which is released when an onion is cut or chopped. This compound evaporates into the air and gets to our eyes, so they produce tears as a defense.

But syn-propanethial-S-oxide isn’t in the onion itself. It’s actually created when certain enzymes and sulfur compounds in the onion’s cells mix. This chemical reaction happens when the onion’s cell walls are broken.

To reduce tears when cutting onions, there are several methods. Chilling the onion for 30 mins before slicing slows down the enzymatic activity and reduces syn-propanethial-S-oxide. Also, using proper cutting techniques and sharp knives that cause less disruption in the cells helps.

Finally, goggles and a slice of bread can provide relief. Goggles act as a barrier between eyes and airborne chemicals. Chewing bread absorbs some of the irritating compounds so they don’t reach our eyes.

Frequently Asked Questions

Q: Why do onions make us cry?

A: Onions contain a chemical called syn-propanethial-S-oxide that is released when the onion is cut or damaged. When this chemical mixes with the moisture in our eyes, it forms a weak acid that irritates the eyes, resulting in tears.

Q: Can all types of onions cause tears?

A: Yes, all types of onions contain the same chemical that causes tears. However, some types may have a higher concentration of the chemical, making them more likely to cause tears than others.

Q: Are there any ways to cut onions without crying?

A: Yes, several methods can help reduce tears while cutting onions. Some suggestions include chilling the onion before cutting, cutting the onion under water, or wearing goggles to prevent the onion’s chemical from reaching the eyes.

Q: Does cutting onions near a running flame help prevent tears?

A: No, cutting onions near a flame or running water neither prevents nor stops tears. While these methods may disperse the chemical in the onion, they do not eliminate it completely, so tears may still occur.

Q: Are there any health benefits to the chemical in onions causing tears?

A: Yes, the chemical responsible for making us cry when cutting onions also has several health benefits. It has antibacterial properties, helps lower cholesterol levels, and may even reduce the risk of certain cancers.

Q: Can wearing contact lenses while cutting onions prevent tears?

A: No, wearing contact lenses while cutting onions does not prevent tears. The chemical released by onions can still reach the eyes, causing irritation and tears, regardless of whether you are wearing contact lenses.

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