This is the first time the alternative method has ever been suggested. Pat Gainer tried it a few days ago and said that it worked, so I decided to recommend it. The high temperature will not damage any of the ingredients so far as I know. I have mixed pyrocatechin, metol and ascorbic acid before at this temperature and there was no problem. You don't need any TEA or water mixing this way.
Originally Posted by john_s
I suspect that you could mix at a lower temperature with a hot plate stirrer but have not actually done so. Pyrocatechin and ascorbic will definitely go into solution at a much lower temperature, not sure about the metol.