Nothing quite makes a backyard barbecue like a hamburger. While condiments like ketchup and mustard are mainstays, onions aren't talked about enough.
In my opinion, the best onion for a hamburger are Vadalia Sweet Onions. If those aren't available to you, the next best option are yellow onions. With that said, I'm also a big fan of red onions on burgers too.
Onions are one of the rare foods that can be sweet, pungent, savory, and aromatic, all at the same time.
The most popular types of onions used for hamburgers are:
Onions are an often overlooked condiment. This list isn't all encompassing, however you'd be safe to use any of these options at a backyard barbecue for friends and family.
To preface this article: I'm a big fan of onions.
Sweet onions tend to be larger than yellow onions and have thinner skin. The result is a crisp, sweet onion that isn't as forward/sharp as yellow onions.
To put that into perspective, when I was younger I used to eat Vidalia's like apples. Now that I'm older, I'll still eat several strips when I'm preparing them for hamburgers.
This is primarily due to the lower levels of Pyruvic acid, a chemical found in onions that gives them their pungency. This is also the reason you cry when slicing most onions. Since Vidalia's have lower levels of Pyruvic acid, they're more sweet and less likely to make you cry.
Vidalia is a particular type of sweet onion grown in Vidalia, Georgia. Similar varities include Washington's Walla Wallas or Hawaii's Mauis.
The reason Vidalia onions are sweet is because they contain less sulfur and less water than yellow or red onions. This is due to the soil they're grown in - it also contains less sulfur due to Georgia's sandy soil.
Vidalia's are also perfect for onion rings as they're large and make for great toppings on a burger.
Of the different varieties of onions - your safest bet are almost always yellow (brown) onions. A big reason is because they're the most common; Most folks have these in their home due to their all-purpose nature.
Yellow onions have white flesh and yellow/brown-ish skin.
Yellow onions tend to have a sharp/strong taste when raw - however, it tends to mellow when cooked/sautéed due to it's sugar content. This works particularly well if you're someone who likes caramelized onions.
You shouldn't be deterred by descriptors like "sharp" or "strong." I'm the type of person who will chop up onions and add it to my ground hamburger mix; I'll then slice up another onion to put on top of my burger.
Yellow onions offer a wonderful textural difference - the crisp/crunch - that is often overlooked with burgers. If you're after a burger that's onion-forward, yellow onions are perfect.
Red onions also work quite well for burgers. What sets them apart from the other varieties is their obvious color difference. Most folks will eat with their eyes first and having different colors improves the eating experience.
While they do work well with burgers, they'll typically find their way into other dishes like salads, salsa, braises, etc.
I'd deem red onions to be more bitter/spicier than yellow onions. In order to remove some of this forwardness, you can soak them in cold water - this also makes them more crisp.
Something a lot of other websites fail to mention is the fact that red onions are wonderful for grilling. I like to cut them up into wedges and then place them on my grill grates when making burgers.
Unlike yellow or sweet onions which will tend to go mushy, red onions will have a jam-like texture alongside the grilled texture from searing on the hot grates.
Pickled onions are also overlooked for burgers and they are quite easy to make.
For burgers with toppings like Jalapenos and other types of hot peppers, the vinegar can help to further enhance these flavors.
The contrasting flavors also enhance the eating experience. Pickling is a process that uses an acidic brine - typically made of things like salt, sugar, or vinegar. This changes the flavor to be more sour.
Hamburgers (typically 80% lean to 20% fat) are usually very rich so adding an acidic note hits all the taste buds.
Rather than simply taking my advice, I figured it would be worthwhile to message a few of the popular Burger joints across America to see what they use.
I reached out to three brands: In-n-out, Whataburger, and Five Guys.
Of these three, Five Guys was the only brand that was super forthcoming. Eventually, In-n-out gave me a meaningful response. At first, they wanted me to call "toll free" in order to learn more about their ingredients.
Whataburger said "Unfortunately, company information that is available to the public can be found on our website."
I mean, I'm not trying to learn the secret formula, just to know the types of onions they use on their burgers.
Kimberly from Five Guys got back to me in 48 hours and said that they use Yellow Onions.
The reason being: "The yellow onions hold up better with the heat of the burger so they do not get soft. It gives that crunch you need in a good burger."
Amanda from In-n-out's customer service team got back to me and said they use Yellow Spanish Sweet Onions.
Amanda went on to say: "We have been using Yellow Spanish Sweet Onion for more than 20 years. The type of onion used has varied slightly due to supply issues over the years, but this is the onion currently used [as of March 22, 2022]."