Why do onions make you cry, and how can you prevent it from happening? They’re made up of a tunic of outer leaves (the brown layer), scales (the white firm juicy edible part), and the basal plate (often called the “hairy part” or the “root”). When you cut the basal plate or shoot, they release an enzyme. That enzyme reacts in the rest of the onion to release a gas. When that gas combines with water, it creates an acid. If that water is in your eye, you have acid in your eye. Whoops.
Onions can lend a sweet, distinct undertone to soups, sauces, and stews. However, cutting them can be frustrating when the technique is unfamiliar. For simple slicing, try this method.
Using a chef’s knife, trim off the stem end of the onion and cut it in half through the root end. Tip: Make sure to use a very sharp knife to help avoid watery eyes.
Peel back the skin on both halves, leaving the root end attached.
Next, make horizontal cuts parallel to the cutting board, slicing to, but not through, the root. Then in the opposite direction, make lengthwise vertical cuts, almost but not quite down to the root.
Finally, cut across the width of the onion to chop into small pieces.
This technique can also be used to finely dice and mince an onion. Simply make more cuts in each direction through each step.
Chill your onions in the freezer for 10 – 15 minutes before cutting them. This reduces the amount of the acid enzyme released into the air and has zero effect on taste. This was found to be the most effective way to reduce tears by the television program Food Detectives.
- The fridge can do it, too; just make sure not to keep them next to apples or potatoes, or leave them in there for too long (20 minutes should do it) — they can cause odors if you do.
Cut the onion under water. This is an effective method, but the problem is that it’s a bit difficult to maneuver. In the water, the onion bits go every where unless you hold onto them and then scooping them up and draining out the onion water and it can all just not be worth it if you don’t execute it right. If you choose this method, plan out your attack beforehand.
- Some say to do it under running water, but this is a bit tricky, too, obviously. The gushing water makes everything go a little haywire in your hands.
Cut the onion near hot running water or a cloud of steam. Steam from a kettle or pan of water will do the trick. The science here is that the steam will draw out the vapors from the onion, dissipating them.
Soak the onion in water. The enzyme is denatured by the water-air boundary. However, do know that this eliminates some flavor and that the onion is a little more slippery than normal (making it harder to deal with). If milder onions are okay for you, give this method a shot.
Use some type of acidic solution. An ionic or acidic solution can denature the enzyme. Here’s a couple home remedy solutions from around the house:
- Put vinegar on the chopping board. The acid denatures the enzyme.
- Soak the onion in salt water. The ionic solution denatures the enzyme. But do know that this can change the flavor.