Reply #3: Before suggesting anything, what are your SO's general tastes like?

[Stinky The Clown]

Each fast food chain has its own proprietary meat recipes. Not only is the meat sourced specifically, but the fat content is precise and there may or may not be seasonings added. All this makes for the greaseburgers we all 'love' to eat. Then there's the cooking method. Although it appears they're either grilled or charbroiled, some (McDonald's, for one) actually incorporate some form of steaming into the process. McD does it with their proprietary grill. The grill elevates the patties just enough to create a void below them that steams as well as grills, using the meat's own juices as the steaming medium. Krystal's and White Castle use a grill with a platen that comes down to cover the patties. In essence, the top grill forms a lid to trap the moisture and, effectively, steam the burgers.

A platen grill looks like this:


It simply isn't possible to duplicate a chainburger at home.

So .... back to my original question ..... what kind of taste sensibilities does your SO have? If he likes big flavors, you may think about taking your burgers in a whole different direction. Almost to a meatloaf type mix with onions (or onion powder), maybe garlic. Even some liquid smoke. Herbs, too. Maybe egg into the meat before forming the patties. The possibilities are endless.

In the post above, my hometown buddy catnhatnh suggested using what are essentially cheap-o burgers. The soy protein additive used by various patty manufacturers is likely (but not absolutely) to be flavored and imparts that flavor to the burger. So you may have to try a few that are available to you before you find one that approximates a chainburger.

Here's one last little secret about meat ....... the meat available to the industry is often different than what makes it to retail channels. The industry gets 'heavy' beef while we get 'light' beef. The difference is in the overall animal size before slaughter. Heavy beef and light beef can both grade the same and are both of equal quality when measured against the same standards. The difference is that heavy beef has a richer flavor. And that's why, even if you could develop the same cooking temperature and duplicate all other cooking conditions as your favorite steak house, you couldn't duplicate their product. You and they are using different raw material.