Untrue, isomerisation is temperature dependant, there is even an equation that describes the rate, yes it happens faster hotter but there isn't an off switch at 85oC.
Given that you get more iso-alpha from no chill (bases on experiment, I'm not convinced that it is all that much) wouldn't you get the same effect from just using less bittering hops? Less hops would mean you get all the advantages of a longer boil and save money on hops.
If you want to understand what's happening to alpha acids in the boil Isomerisation.pdf
Mark
Given that you get more iso-alpha from no chill (bases on experiment, I'm not convinced that it is all that much) wouldn't you get the same effect from just using less bittering hops? Less hops would mean you get all the advantages of a longer boil and save money on hops.
If you want to understand what's happening to alpha acids in the boil Isomerisation.pdf
Mark