Why Are McDonald's Onions So Good?

Whether you find yourself under the Golden Arches because you want to treat yourself to a tasty meal or simply because it's a convenient stop, there's no denying that you're going to enjoy your food. We get it, food at McDonald's really is on another level.

It's hard to resist a burger from McDonald's — come on, that's literally their specialty. So while chowing down on your Big Mac have you ever gotten a bite filled with oniony goodness and thought that might be the best onion I've ever tasted?

Why Are McDonald's Onions So Good?

Seriously, McDonald's onions are different and, some may say, better than onions from other fast food restaurants, and maybe even onions that you use at home. That's because McDonald's uses two different types of onions, depending on what you order.

"McDonald's uses both dehydrated onions (that have been rehydrated) as well as actual onions," according to Angel Livingood, a former manager at an Iowa McDonald's.

Dehydrated onions are exactly what they sound like: onions that have had their moisture removed and are now dry. This is the same idea behind the granulated onion and onion powder found in your spice cabinet. The dry onions are shipped out to the stores and the McDonald's employees rehydrate the onions by soaking them in water.

The rehydrated onions are on most of the sandwiches, like the Big Mac, McDouble, and classic hamburgers, but fresh onions are used on all Quarter Pounders. A good way to know if you're getting rehydrated onions or actual onions is to look at how they're cut. The small chopped onions are rehydrated while the slivered onion slices are fresh.

However, Livingood confirms that you can ask for either on any sandwich. So if you prefer the fresh onions to the rehydrated ones, you can ask for those on your hamburger instead.

But if you order anything other than a Quarter Pounder (or one of its many varieties), you may be used to the taste of the rehydrated onions. The reason you probably love those onions so much is because they taste less pungent and spicy than a regular raw onion. The dehydration process allows the onions to keep their sweet flavor, without the added bite of freshly sliced.

More About Dehydrated Onions

"Drying alters the chemical makeup of the onions which in turn reduces the pungency of the onions. The moment you slice (or bite) into it, enzymes, called allinases, spill out of the cut cells and start converting tasteless compounds into thiosulfinates, which are the spicy/burning chemicals in onions," says Michael Nestrud, who has a Ph.D. in Food and Sensory Science as well as a culinary degree from the Culinary Institute of America (CIA).

Not only are rehydrated onions downright delicious, but they also make sense for McDonald's to use from a business perspective. Shipping dehydrated onions to the restaurants will save McDonald's money, plus dried onions have a longer shelf life and more uniformity than fresh onions, explains Nestrud. After all, McDonald's was built on the idea that customers should have the same experience at every restaurant. So no matter where you go, the onions will always taste the same — just as McDonald's CEO Ray Kroc intended it.

How to Make McDonald's Onions At Home

If you're looking to recreate McDonald's onions for a copycat Big Mac or another onion-topped meal, they're actually surprisingly simple to make. Of course, you could buy dried onions and rehydrate them yourself.

Or, you can follow Nestrud's CIA trick. Simply sharpen or hone your knife — that way you won't cut as many cells — then dice your onion. As soon as you're done dicing, run the onions under water for 30 seconds to 1 minute. This "physically removes those enzymes from the cut surfaces and accomplishes a similar effect [to McDonald's]," says Nestrud. Be sure to shake off the extra water so you don't end up with a soggy burger bun.