Fact: We love all cheeses, from fluffy clouds of Burrata to thin slices of Vermont cheddar and everything in between. But when it comes to grilled cheese sandwiches, not all fromage is created equal.
According to the American Chemical Society, the secret to getting that gooey, stringy, melty perfection has to do with the pH level of the cheese.
Here's the deal: Lower pH levels mean that when heated, the cheese will stretch and melt easily. Higher pH levels mean it will release its oils when grilled and result in a greasy, lumpy mess. (Ew.)
Your best bet is to sick with these varieties: Manchego, Gruyère, Gouda and mild cheddar. (Those processed slices of American will do a decent job, too.)
So what are you waiting for? That bread isn’t going to butter itself.