The Surprising Vegetable You Can Use to Clean Your Grill, According to a Chef

The first time I met chef and cookbook author Bricia Lopez, she was standing over a grill on top of a mountain in Aspen, Colorado, at the Food & Wine Classic. Lopez was gearing up to host an asada, complete with juicy tacos, smoky salsas, and cold drinks. With the achiote-marinated chicken thighs ready to be seared over the flame, I watched as Lopez cleaned the grill. To my surprise, rather than grabbing a wire grill brush, she reached for an onion.

She cut the onion in half, picked up one piece with tongs, and used it to scour the grill grates. Even with the picturesque snow-capped Rocky Mountains as the backdrop, my eyes were fixated on the onion gliding over the grates. The pesky bits of blackened schmutz from food grilled before effortlessly wiped right off. Lopez was ready with an explanation when I asked her about the technique. “I have actually been cleaning my grill with an onion all summer long — I call it the sacrificial onion. It not only brings a beautiful aroma, but it almost creates a nonstick surface, perfect for your proteins or vegetables,” she says.

An onion’s natural acidity helps release stuck-on grease and grime in seconds. (Juicy chicken, flaky fish, and tender vegetables are less likely to stick to clean grill grates.) Plus, with an onion, there’s no fear of a wire brush leaving behind small bits of metal that could end up in your food. “Onions contain a surprisingly high amount of an antimicrobial compound" known as allicin/isoallicin, Lopez reports. "It's a win-win.” 

Using an onion to clean grill grates is simple. Preheat the grill to the temperature you plan to use for cooking, for at least 15 to 20 minutes. The heat loosens grease and bits of stuck-on food, making the grates much easier to clean. Slice a large white onion in half; there’s no need to remove the peel, and reserve one half for another use. “White onions work best for this, the bigger the better. I've tried it with red onions and they don't work as great,” says Lopez. Hold one onion half with tongs and rub the onion, cut-side down, over the grill grates. Once the grates are thoroughly cleaned, push the onion off to the side and begin grilling, reserving the onion to rub over the grates throughout cooking as needed. When finished, simply compost or discard the spent onion half and start fresh next time you fire up the grill.