How to Reduce the Sharpness of Raw and Cooked Onions in Your Food
The longer they sit in the ground, the stronger they become.
Onions are essential ingredients in so many recipes. From something as basic and versatile as sautéed vegetables to Bolognese sauce, risotto, salads, stews, and even dips, onions are a star player. But if you're not a fan of their sharp flavor—raw or cooked—there are a few genius ways to make them smell and taste more mellow.
Why Are Onions So Potent?
Before we discuss how to make them less intense all around, it's important to understand what makes onions so potent. When you cut into an onion, an overwhelming smell takes over and your eyes suddenly start to well up. That's not because this is a particularly mean vegetable—it's all thanks to sulfur. "Sulfur is what builds up in the layers of the onion. When you have a large onion, it's going to be stronger because it's spent more time beneath the ground. The longer an onion sits in the soil, the stronger the sulfur will be," explains Palak Patel, a chef and educator at the Institute of Culinary Education.
When you cut an onion, chemical enzymes within the cell structure of the bulb escape and react with oxygen, which causes an irritant that makes you cry. Cut onions at the last minute and immediately start to cook with them in order to prevent the enzymes from interacting with oxygen. The enzymes float into the air and react with the surface on your eyes.
Does Age Correlate with Potency?
Two factors that indicate the age of an onion are the size of the bulb and structure of the skin. The bigger the onion, the more sulfur that has built up in its many layers. For example, you may find both small and large yellow onions in the same section on a grocery store shelf; choose the ones that are smaller, since they'll taste and smell less potent. Another surefire sign that an onion is old? If the skin is flaking and peeling easily.
How to Reduce the Sharpness of an Onion
Patel recommends soaking a sliced onion for 30-60 minutes in ice water, which will alleviate some of the enzymes from escaping. Drain and pat dry before cooking with the crisp, palatable onion. If you're short on time, you can stick an unpeeled onion in the freezer for just a few minutes or rinse it under cold water, which will also help to dilute the intensity of the enzymes. "Water, a quick pickle of cut onion in vinegar for a few minutes, or any kind of acid will also dissolve the enzymes and take the bite out of the onion," says Patel. And if you're really against using strong onions, stick to a milder variety such as white or Vidalia onions, shallots, or spring onions.
Breaking Down the Enzymes
Whether raw or cooked, there are a few things you can do to do make an onion milder. Think of French Onion Soup. The flavor of this classic recipe is sweet, rich, and ultra-comforting. This is because the onions have cooked low and slow, which breaks down the enzymes and ultimately makes the onions taste really sweet. "The longer you cook an onion, the softer and sweeter it gets," says Patel. She recommends cooking the onions with plenty of fat (think: butter or oil), which also helps to offset the volatile onion flavor.
Onions also pair well with salt and citrus. "I love serving raw cucumber, tomato, and red onion salad with lime juice and cilantro—like an Indian version of pico de gallo that is cooling," says Patel.