An internet rumor states that White Castle onions are not really onions. Instead, they are little pieces of cabbage that have been soaked in onion juice. This rumor is untrue! White Castle uses reconstituted dehydrated onions on their burgers, as they have since World War II. There is nothing unusual about this in the fast-food burger industry. McDonald’s uses dehydrated onions on all its standard burgers except the Quarter Pounder.
🧅Why dehydrated onions? White Castle switched to dehydrated onions when fresh onions were in short supply during World War II. It turned out that the dehydrated onions were superior to fresh for their cooking method, so they never switched back!
How Does White Castle Cook Their Burgers?
To cook their burgers, White Castle starts with a big layer of steaming minced onions on the grill. They then place the little square burger patties (with holes in them) on this bed of onions. It’s the steam rising up from the onions that cook the patties, infusing them with onion flavor. At the end of the cooking process, the top bun is placed on top of the patties as it cooks, and the steam rise up to also infuse the top bun.
The onions on White Castle burgers are an integral part of the recipe. Without the onions, a White Castle slider would not be a slider at all. Not only do they impart flavor, but the steam moistens the bun, resulting in that soft, moist, oniony goodness that just “slides down your throat.” Hence the nickname “sliders.’
If the onions weren’t onions, that would be a strange twist! The video below shows how White Castle cooks their burgers.
Why The White Castle Onions Cabbage Rumor is Silly
Cabbage cooked on a grill does not have the texture of onions, and the cabbage would cause a bitter taste. What’s more, soaking cabbage pieces in onion juice would not make them taste like onions or behave like them! They would taste like oniony pieces of cabbage.
The other thing to consider is why in the world the company would want to do this. Purchasing onion juice would not save money. Dehydrated onions are much less expensive than a combination of cabbage and onion juice.
Anyone who thinks that the onions on a White Castle burger are not onions has likely never been to White Castle, nor eaten any onions, it seems. It is a ridiculous myth. A rare version of this myth has turnips being used as an onion stand-in. This, of course, is just as silly as cabbage.
👩🍳Lore Highlight: Did I say “grill” instead of “flat top?” Yes, indeed! Flat tops are routinely called grills in the short-order and fast-food business.
The next time you’re in the spice aisle at the grocery store, look for dehydrated onion bits, and you’ll see the same kind of onions White Castle uses. They rehydrate them first, of course!
White Castle Onions FAQ
Are the onions at White Castle really cabbage? No, the rumor that White Castle uses cabbage soaked in onion juice is a total myth. The “onions” are actually 100% real onions that have been dehydrated and then reconstituted with water on the grill.
What kind of onions does White Castle use? White Castle uses minced, dehydrated onions. This practice began during World War II due to fresh onion shortages, and the chain continued using them because they are ideal for the “steam-grilling” process that gives sliders their signature flavor and soft bun.
Why do White Castle onions taste different? The unique taste comes from the steam-grilling method. The onions sit on the flat top under the burger patties, which have five holes to allow onion-infused steam to pass through and flavor both the meat and the bun simultaneously.
Does White Castle put cabbage in their burgers? No, there is no cabbage in a White Castle slider. Using cabbage would not only be more expensive than dehydrated onions but would also result in a bitter taste and a texture that doesn’t match the signature slider experience.
