What's the difference between grilled and caramelized onions?

You know what’s a fantastic flavor booster? Onion! Whether grilled or caramelized, onions pack a potent yet pleasing punch to your palate. Up until a few months ago, however, I never really knew the difference between grilled and caramelized onions. Aren’t they the same? No. They are not.

I’ve always enjoyed the taste of onion, but, these days, I almost exclusively stick to the cooked variety. In fact, after encountering raw onions one-too-many times on a Chicago hot dog as a kid, I had to swear off them entirely (for the most part!). Why? I have a hard time digesting them. Without getting into too much detail, raw onions seem to always spark a battle against good and evil within my stomach.

Luckily, I learned that cooking onions removed some of the more…unpleasant digestive characteristics common to raw onions—at least for me. So, whenever I’d need a boost of flavor in my meal prep, I’d add some cooked onion. It’s great in Tuscan pasta, meatloaf, on brats, on burgers, or by itself as a side. In the past, what I did to cook them was simple: I’d either slice them up and sautee them in a pan with cracked pepper and olive oil, or I’d wrap them in foil and plop them on the grill. Once they turned translucent, I knew they were safe for my consumption.

The thing is, I began to take notice of the cooked onion served at restaurants, and they tasted…different. They were simultaneously sweeter and more savory. They were stronger. They were darker. They were referred to as “caramelized.” At first, I just thought a caramelized onion meant charring the onion. “That’s the darkness and sweetness,” I thought. Wrong! Embarrassingly wrong. Attempt after attempt, I couldn’t get it right. Instead of sweet, they just tasted burnt. Because I burnt them.

Enough! I had to find out what I was doing wrong. I couldn’t continue this trial and error in ignorance. So, I did what any normal person would do and headed to the Google. There, it became obvious that I was cooking too short and too hot. I came up with a meat-based analogy to help me remember what we’re dealing with. Here it is: Barbecued meat is to grilled meat as caramelized onion is to grilled onion. Whereas grilling in each case requires high heat and faster cook times, barbecuing and caramelizing require you to adopt a low-and-slow mantra. In order to move from grilled onion to caramelized onion, I needed to adjust my cooking temperature, and, therefore, cook times.

Grilled onions are cooked at high heat. Depending on how hot and how direct you get that heat, you may not need more than 5-15 minutes. If you like your onions to come out a bit crispier (or burnt) you just turn up the heat and/or leave them on for a few extra minutes. Each piece of onion will keep its integrity, but the color will be more translucent in nature (maybe with some browned edges), and the consistency will move from crisp (raw) to soft (the longer it’s grilled, the softer it’ll be). You’ll still get an onion flavor, but it will be a lot more mellow.

Caramelized onions are generally cooked at medium-to-low heat. Depending on how low and how indirect you get your heat, you might need to leave yourself about 45-75 minutes to properly caramelize an onion. Instead of charring or burning the sugar, you’re browning it. Actually, you’re oxidizing the sugar. This produces a sweeter flavor than either grilled or raw onions. It also turns the onions a brown color, throughout, and yields a jam-like consistency. The flavor will be richer and deeper than a grilled onion. Because of the immense water loss (via steam), one onion will not yield much once caramelized. A good rule is to assume every two-and-a-half raw onions will produce about one cup of caramelized onions.

In my experience, I’ve found caramelized onions to be fancy and flavorful. If you’re looking to kick a meal up a notch, I’d go with caramelizing onions over grilling them. Still, grilled onions have their place—like atop a brat! Curious about how you can take onions from grilled to caramelized? Check out these recipes:

In a Skillet

Perhaps the easiest way to to caramelize an onion is on the stovetop in a skillet or pan. It also gives you an up-close look at the many transformations the onions go through on the way to caramelization—in case you want to keep tabs on everything. Try this recipe.

In a Slow Cooker

If you want to ensure that your onions get cooked low and slow, and you just want to throw in the ingredients and forget about them until done, slow cooker cooking is for you. Check out this recipe.

On The Grill

If you don’t have a slow cooker, or you like to make everything on the grill, go right ahead! Set your heat to medium. Then, slice up your onion as you like. Next, place up to two onions in aluminum foil. If cooking more than two onions, use another sheet of aluminum foil. Cooking smaller batches will ensure more even cooking. Then, fold the foil upwards, into a bowl. Don’t close/seal it—you want steam to get out. Finally, put some olive oil or butter atop the onion, and place it on the top rack, or on medium-to-low indirect heat. Give it about 45 minutes, then check to see the coloring. Cook for additional time, per your preference. The lower, and slower you go, the sweeter they’ll be.

When I’m in a pinch and need to get food on the table in a hurry (almost always), grilling an onion is just fine by me. But when I want to impress folks and have a little bit more time to prepare, caramelizing never lets me down. As with most things food, it’s all about personal preference. But next time you decide to cook an onion, remember: You have a choice. Now that you’re fully informed, it’s up to you to choose wisely.

Related Video: Caramelizing vs Sweating Onions

Header image by Chowhound, using photos from Fox and Briar and Chowhound.

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