You might assume that alcohol is what gives bourbon its heat. But veteran tasters know you would be wrong. PHC at barrel strength, for example, has a lot less burn than Benchmark Old #8 at 80pf. So, there must be other chemical and/or esthetic factors that contribute to our perception of heat.
A corrolary: I think wheated bourbons tend to taste sweet because the underlying corn is not masked the way it is by the more pronounced spice of rye.
What accounts for heat if it isn't the alcohol? Any of you chemists or other bourbon geeks know what might mask the burn? (Unless, of course, I'm totally wrong and it is the alcohol.)