Simple "2 dos and 1 don't" to chop onions tear-free

Simple "2 dos and 1 don't" to chop onions tear-free

Why do onions make your eyes tear up when cut?

The reason is that onions release an irritating chemical that stings our eyes. Onions are mostly water plus some vitamins and sugar compounds.

They also contain sulfur compounds, a naturally occurring chemical found in many odorous substances, such as skunk spray that smells like rotten onions and garlic. This is one way plants defend themselves by producing repellents against organisms that might attack them. Other plants have thorns or spiny leaves, or are made up of specialized cells that make them tough to chew.

A sulfur compound found in onions, known as propyl sulfoxide, is released into the air when you slice an onion.

Accordingly, upon contact with moisture—such as water vapor in the air or natural moisture around your eyes—it transforms into sulfuric acid. Sulfuric acid has a pungent odor and irritates the eyes, causing them to produce tears to wash it away.

If your eyes are already watering while cutting onions, do not use your hands to wipe away the tears. This will only make your eyes sting more, as hands carrying onion compounds come into direct contact with the eyes, according to The Daily Meal.

How to chop onions without crying

Onions stored for a long time often contain higher concentrations of sulfur than freshly harvested ones. For optimal results, you can combine two to three methods (such as chilling while using a sharp knife) to make your cooking experience more pleasant.

Chewing constantly

Chewing gum or having any food in your mouth encourages breathing through the mouth, which sucks in tiny droplets before they can rise into the eyes.

Chill onions in the refrigerator before cutting

Chilled onion cells react more slowly when cut. Therefore, place onions in the refrigerator for at least 30 minutes before cutting and peeling, or put them in the freezer for 10-15 minutes (depending on the size of the onion).

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Cut onions underwater

Cutting onions underwater or under running water will also help significantly, as water dissolves the sulfur compounds before they can reach your eyes.

Rub potato on both sides of the knife blade

Rub a fresh potato slice over both sides of the knife blade, then chop onions and chilies freely without worrying about eye irritation.

Holding bread in the mouth

There is a handy tip: if you hold a slice of bread (or any food) in your mouth while cutting onions, your eyes will not sting. This tip stems from the belief that if you do something that forces you to breathe through your mouth, your nose will be less irritated, and you will therefore shed fewer tears.

Vinegar

Spray a 50/50 vinegar-water mixture onto the cutting board because vinegar can halt the sulfur reaction. If that mixture is not effective enough, try spraying pure vinegar onto the cutting board. However, this may affect the flavor of cooked onions.

Use hot steam

To avoid stinging eyes, simply chop onions where hot steam is rising, such as near a kettle.

Chilling onions

One of the most effective methods is placing onions in the freezer for about 15–20 minutes before cutting. At low temperatures, enzyme activity is significantly inhibited, while the evaporation rate of sulfur compounds is also reduced. This is a way to slow down the chemical transformation right from the start.

Use a very sharp knife

Using a sharp knife is the key mechanical factor in reducing eye tearing. A sharp blade makes clean cuts through plant tissues, minimizing crushing and bruising of the cells. The less cell damage occurs, the fewer enzymes are released into the air. Conversely, a dull knife "crushes" the onion surface, driving the release of irritating gases to maximum levels.

Turn on a fan

Turn on a fan blowing in the same direction you are facing to blow away the onion droplets released while chopping.

Cut onions under running water

Many experienced chefs often slice onions under a gentle stream of running water or in a bowl of clean water. Since the pungent compounds are highly water-soluble, the liquid environment absorbs the gas as soon as it escapes from the cut surface, preventing it from reaching the eyes.

If you don't want to cut onions underwater, you can set up a small fan blowing sideways across your cutting board. The airflow will push the gas molecules away from your eyes.

Rub vinegar onto the cutting board or knife

An acidic environment can reduce enzyme activity. Applying a little white vinegar to the surface of the knife or cutting board before cutting will alter the pH on the cut surface, partially inhibiting the enzyme alliinase reaction. This simple tip brings surprisingly effective results.

Keep the scallion roots:

Usually, the root base of an onion has the highest concentration of sulfur compounds. Therefore, a classic chef's tip is to cut the top off first, peel, dice, and leave the root end to be cut last (or discard it whole).

Wear protective eyewear

Another simple way to protect your eyes from the stinging vapors of onions is to wear eye protection. Swimming goggles or gardening goggles both work well, as long as they seal off your eyes.