The Onions That Are The Absolute Best For Grilling

Many folks underestimate just how good grilled onions are as a side dish, and underestimate even more how complex making them can be. As with any dish, it all starts with picking the best produce for the job, but the staggering number of varieties available can be a bit overwhelming. There are just so many types of onions out there that it's genuinely tough to know which ones are best for grilling — unless, of course, you get some advice from an expert.

According to cookbook author and chef Jenn de la Vega, you'll want to go with Georgia's official state vegetable if you're serious about grilling onions. "I like extra-sweet large Vidalia onions on account of their caramelization," she wrote in an exclusive Q&A with Chowhound. Vidalias are known to be an especially sweet variety of onion, so much so that other types just don't cut it as substitutes.

"White and yellow onions are sharper in flavor and benefit from quicker or raw applications. Red onions are in the middle in terms of sweetness and sharpness," de la Vega explained. You may have more luck with other sweet varieties of onion you may have stocked up on, but if you can get your hands on some Vidalias, they're definitely worth popping onto the grill.

The secret to why Vidalia onions are amazing for grilling lies in the soil they grow in. This particular variety grows exclusively in Vidalia, Georgia, where the soil tends to have a lower sulfur content than in other regions. While sulfur is an important mineral for plant growth, it also causes onions to develop more of the compounds that make them pungent and onion-y. The higher the concentration of sulfur in the soil, the sharper an onion will taste. Conversely, the lower the sulfur, the milder these flavors will be.

At the same time, this allows the onions to produce more sugars, which is why the Vidalia onion tastes sweeter than other types. When you pop a Vidalia on the grill, those sugars will caramelize, developing deeper, nuttier flavors. When these sugars are heated with the amino acids present in onions, it also triggers the Maillard reaction, which further enhances the onions' natural sweetness.

As a bonus benefit to having less sulfur, Vidalia onions are also less likely to make you cry. The science behind why onions cause tears in your eyes heavily involves reactions between sulfur compounds and the enzyme allinase; the less sulfur in your onions, the less chances of it creating any irritants. It's likely that the only tears you'll be producing are the tears of joy you get from eating a perfectly grilled Vidalia onion.

For drool-worthy onions, Jenn de la Vega recommended grilling those Vidalias by halves. "Chop off the top, peel off the outer layer of paper, and keep the 'hairy end' intact so the onion will hold together as you grill it. I like to get a good sear and char on the cut side of the onion, and flip it to get some blistering on the other side," she said.

She then suggested letting them cool enough to handle before cutting off the root end. This, she explained, allows the layers to release into petals. At this point, you can return them to the grill over low heat to soften them further, or chop them thinly and grill in a basket over high heat for fajitas. As a rule of thumb, use direct heat if you want a firmer onion and stronger char, and indirect heat if you want softer caramelized onions.

De la Vega also advised going easy on the olive oil if you're using it to prevent sticking, as dripping oil can sometimes cause flareups on the grill. Her last tip was to season the onions only after they start making some noise: "I tend to salt after I hear sizzles because they have released some water, and salt can stick better to them," she shared. Add in a few of these other tips for making the best grilled onions, and you'll have perfect results virtually every time.