And that's the problem, the only way we would ever know what exactly occured in a boil is to have the wort analyzed. Anyone have a lab setup in their basement? Still, there are all the elements necessary to produce caramelization. Heat on the bottom of the kettle, (which I'm going to create an experiment to attempt and get a good reading on), sugar(s) in the wort, oxygen from H2O as steam is generated at the bottom of the kettle and rises. What's missing?