As you can tell, the first Hack concerns onions. There is a real science behind this Hack. Perhaps too much for the home cook to even want to understand. To boil it down: when you cut an onion, it releases sulfenic acid which then changes into other compounds as soon as they make contact with the air. These are the chemicals that burn your eyes so much.
Some people think it's the variety of onion that makes a difference, but the more precise truth is that it's where the onion is grown and in what type of soil that matters most. Sweet onions grown in less sulfur rich clay soils in places like Georgia contain less sulfur to start with.
All you really have to remember is to buy only "Sweet Onions" (this is what they are called in the U.S.). You will find them called Vidalia, Maiu Sweet, Mayan Sweet, Walla Walla, etc.
Do NOT use the bagged, smaller sized "yellow" onions. These are storage onions, and as such, their level of sulfur compounds increase as they age and when cut, they really burn your eyes.
Sweet Onions (we buy Vidalia unless making something requiring large amounts of onions, like French onion soup) are typically much larger and often a flatter, less round shape. They are also wetter than "storage" or bagged onions. As onions sit for long periods of time they dry out. The higher water content in large sweet onions help dilute the sulfur compounds. The dryer the onion, the more likely it will make you cry.
Here's a ranking with the LESS TEARFUL types on top:
- sweet onions (Vidalia, Walla-Walla, etc.)
- green onions (scallions)
- red onions
- smaller, bagged or "storage" yellow onions
- white onions
Good luck keeping those tears at bay...