Also, a study from a University in Hawaii I can't find at the moment indicates that extracting in an aqueous solution of 140 degrees Fahrenheit yields the highest percent kavalactones released. A lot of work was put in the kavaforums with the consensus that this temperature will not 'kill' any kavalactones.
Do you have the paper for that study? An AS would be very interesting to analysis. I wouldn't think heat destroys kavalactones specifically, they are fairly stable.
I did some experiment on my own (the only person I could find documented on the web) about the effects when mixed with Usnea lichen, Old Man's Beard. The quote that drew me to it was from Kava: The Pacific Elixer: "For example, on Pentecost, Vanuatu, to over inebriate a pretentious kava drinker, a lichen (Usnea sp.) is mixed with the rootstock before grinding. The potent effects of this drink may be explained as a synergy between the kavalactones and certain lactonic acids contained in the lichen (Molho, personal communication, 1984)". So I tried it. And it was different, it was sort of.. glossy, if you know what I mean. It had an energy to it, a rush, it was pretty cool... definitely different from the normal kava buzz. But I had deleted almost all traces of myself from that forum and unfortunately so was that well documented experience and resulting experience. Felt weird to be the only dude found on the internet writing about the experience, considering I am not incredibly knowledgeable with chemicals to determine how they interact and just try things based on anecdotal evidence. But I love kava so I'll talk about this all day and answer any questions you may have!