There are some things we may prefer not operate at their full potential. Congress comes to mind right away. Local law enforcement is another institution I have no interest in being operated at its full potential. The Jehovah's Witnesses, Al Sharpton, and George Bush are a few thing I hope never operate up to potential. A friend's car is capable of speeds in excess of 150 mph. He best not operate the vehicle to its full potential, because he had too few points left on his license right now. HI might be another thing that really needn't be used at its maximum potential.
I'm only half joking, and I know none of the analogies are chemistry analogies.
I noticed long ago there was direct correlation between hot cooks and tweaky dope. I learned later that part of tweak is the result of the dry-hot-fast start. Not all of it. Most of the more notorious by-product side effects-- the real tweaker stuff--is produced in hot cooks. Black helicopters, shooting sparks, faces in the woods, voices in the air ducts, people talking outside the fourth floor windows... all seem tied to hot cooks. How hot is hot? Hot is hotter than 120C. Even at 120, some tweaker characteristics start showing up.
At one point, I noted the temperature of the reactions I did to determine the effect of temperature on tweaker characteristics. As them temps went down in my admittedly drier and shorter push-pull type cooks, the tweaker effects dropped out. Sparks disappeared first, helicopters next, then the faces in the woods and general paranoia disappeared (at least until sleep deprivation supplied the effects.) The voices and shadow peeps all took leave of my dope in the range under 120C. Around 120C or a little above, the product would have tweaky effects. Below the 120 mark, there were fewer such problems, and the problems disappeared as the temperature fell to the 100C range. Doing a number of six hour cooks that were still too dry, I concluded that quality meth could be produced in reactions done below 100C which would not have the tweaker characteristics. I learned that if I increased the temperature to the 110-115C range, the tweaky effects began recurring, and any temperature higher than 120 seemed to guarantee such effects.
I finally listened to reason and did a wet reflux, then a long wet reflux, then did one with no noticeable activity to start, no real show or smoke or drama. Just a wet reflux for 36 hours or 48 hours, at an easy, just below 100C temperature. The product of such a reaction done with clean pseudoephedrine is superb. The product lacks any adverse tweaker characteristics. It can produced consistently at this quality without difficulty and without a great deal of experience. Low temperature is one key to the quality and absence of unwanted side effects.
I have not duplicated the side effect experiments doing the long wet reflux, as I frankly have had no reason to repeat them. A 100C temperature produces meth that is as good as it gets with the red phosphorous method.
I started doing hypo synths, and learned quickly to keep the temperature low for that synth. I did not reflux for several hours while doing those, but concentrated the hypo and did a slash and burn fast reduction that was remarkably complete compared to my red phos reactions at the time. I never did the hypo synth as high as 120C without having a phosphine fire at some point.
When I started doing the phosphorous acid synth, I was using a deep fat fryer that would not bring the temperature in the flask to 120C at it hottest setting. The maximum temperature I could attain was 115C. Yet the product was unmistakably excellent. I noticed, however, that even with a longer reflux, temperatures lower than 110C did not give me the quality of product that I obtained at 115, and finally 120C. I changed heat sources and refluxed the phos acid reaction twelve hours at 120C; I was delighted with the results. I had very good product and an excellent yield. My most recent phosphorous acid reaction was done with with very well cleaned freebase pseudo at the higher temperature range, measured by the hot plate settings and the observed activity in the flask. I did not set a thermometer up to test, as I have-- once again-- broken all of them. The last reaction yielded meth that was as good as any I have produced in the last year. No tweak. Solid meth. Clean, smooth, and effective.
I am of the opinion that the phosphorous acid synth does its best work in the 120C range. I am not so inclined with the hypo synth, but my opinions there are tied to instances of phosphine fires. As to the red phosphorous method, at least for the long wet reflux done with actually clean pseudo, I believe that a 120C temp might be an optimal temp. I also believe that unless the pseudo is very clean (and I am of the opinion that very few cooks actually have very clean pseudo) a red phos cook done above 110-115C is an invitation to tweaker dope. Make the red phos reaction a drier push-pull reaction, and 120C guarantees tweaky characteristics. At least in my experience.
Maybe the fact that the typical clandestine meth cook is done with less that perfect precursors under less than optimal conditions mitigates against pushing the temperature of the red phos reaction to the optimal range. This observation could be a misunderstanding of what I have observed over time doing these synths. I belive the tweaky street dope is like that partially because the feedstock pseudo is not as clean as the cook thinks. The balance of the tweaker characteristics are, in my opinon, realted to the temperature of the cook. The STE, STB, and Tetra trap methods, as well as the EGull and derivatives, do not routinely yield completely clean pseudo feedstock. There has to be some workup beyond the base techniques with most OTC pseudo sources. The pseudo obtained by faster extraction methods will react pretty well, but will usually contain something in addition to pseudo. Few street cooks clean the pseudo to an actually clean state. I know a number of bees who have never really gotten pseudo all the way clean, and who would likely not recognize really clean pseudo when they saw it. The pseudo's purity must be considered when you mull running the HI reaction at its maximum potential.
If you admit that most of the synths, and in particular the red phosphorous synths, are done in less than ideal conditions with less-than-pure precursors, cranking the heat up to 120C to optimize the HI may very well do nothing of benefit to the product made by these cooks. It may be better to back off ten or fifteen or twenty degrees, take more time, and be patient. I for one will likely continue to do red phosphorous reactions under the 120C mark, and will do the phosphorous acid cooks at the 120C mark. I do that based on my experience doing these synths, and evaluating the product produced.
It could easily be true that the clandestine cook does not really want to do this reaction at its optimum potential. That may be one of those things that we don't realy want to work to to its potential in real world conditions. The idea that there is a temperature at which the reaction will work best or at its highest potential does not necessarily mean that the clandestine cook, or his product, would be advised to crank the heat up to that temperature.
Then again I could be completely wrong. It would not be the first time, by any stretch of my imagination.