An awesome lesson of grilling that had not occurred to me before.
The secret to toasty buns is in the physics
Anytime you cook light-colored food with high heat, inattention is a recipe for disaster. But the physics here is pretty simple, and once you understand it you can use several methods to improve your odds of making that perfectly toasted bun, golden half-melted marshmallow or juicy grilled fillet.
At high temperatures — about 400 degrees and up — a substantial part of the heat that reaches the food arrives in the form of infrared light waves rather than via hot air or steam.
A lesson that one also sees in discussions about global warming: white-ish things, like the above-mentioned buns marshmallows or fish, reflect much more radiation than darker things. So as your food item begins to brown (or your Arctic ice melts), it absorbs the heat much faster, and correspondingly cooks faster. A potentially disastrous feedback effect.