The Anatomy of a Sweet Onion

1. Look at the Skin

The skin is your first and best clue. A pungent onion has a thick, dry, and often crinkly outer layer that can range from deep yellow to reddish-purple. A sweet onion, however, typically has a much thinner, almost translucent skin. The color will be lighter—a pale white, light yellow, or even a pale golden hue. A delicate, papery skin is a good indicator that you’re looking at a sweet variety like a Vidalia or Walla Walla. Avoid onions with bruised, moldy, or discolored skin, as this can be a sign of spoilage.

2. Feel for Firmness

The next step is to give the onion a gentle squeeze. A good, fresh onion should be very firm all over. It should feel solid, with no soft spots or mushy areas. A soft onion indicates rot on the inside and will be more pungent and unpleasant to cook with. While sweet onions have a higher water content, they should still feel dense and firm to the touch. Avoid any that feel spongy or have any give when you press on them.

3. Check the Shape

This isone of the easiest ways to distinguish a sweet onion from a regular one. Regular onions tend to be perfectly round or oval with a pointed top and bottom. Sweet onions, by contrast, are almost always flatter in shape. They have a noticeably wider, more squat appearance. This distinct shape is a natural result of the way they grow and is a reliable sign of a sweet variety.

4. Examine the Neck and Root

The top (the neck) and the bottom (the root) of the onion can tell you a lot about its freshness. The neck of the onion should be dry and tight. It should not be green, slimy, or moldy. A green shoot sprouting from the top means the onion is old and has started to grow again. When an onion begins to sprout, it uses up its sugars, making it more bitter and pungent. Similarly, the root end should be dry and clean. Avoid onions that have any sign of moisture or mold on the ends.

5. The “Smell Test”

This final test can be a great way to confirm your suspicions. If you hold a sweet onion up to your nose and gently sniff, it should have a very mild, almost non-existent onion aroma. The classic sharp, eye-watering scent that we associate with onions is the result of sulfur compounds. Since sweet onions have less of this, they should smell much less potent. A strong, powerful onion smell is a clear sign that you’re holding a pungent variety, no matter what the label says.

By using this simple five-point checklist, you can move beyond relying on guesswork and become an expert at choosing the perfect sweet onion. Remember to look for a flatter shape, a firm feel, and a thin, pale skin. By taking a moment to inspect your produce, you can guarantee that your next dish will be infused with the perfect, mild flavor you intended.