Do you taste the "butane"
@Jimagic?
Short answer: I don't.
Looong answer: This is a timely question, seriousT. We're just, this week, producing new footage for the torch instructional and I'm writing the more detailed technique language for the site etc.
Given the endless nature of the interwebs it would be dumb to say I've read everything out there on blue flame heating, but over time, I've studied a bunch from what I think are the most relevant voices: connoissseurs of food and cannabis, where the issue of "torch taste" has been studied and debated pretty endlessly. Because all of those opinions are clicks away I won't belabor the science but I'll summarize the technique that I think makes MS very clean.
We all know a true blue flame means the oxygen is properly premixed and the fuel is being fully burned with the hottest region being at the tip of the inner, more translucent point (appr 2500 F). First we recommend lighting the torch away from the intake so there's no initial unburned fuel to draw, then placing that point well above the intake as well as the extended outer flame. You don't want the flame, but the pure heat that it's generated after burning off any residual elements of the fuel. You're warming the stone and the stone chamber and the heat being driven above the intake might be 1000 F or so; but it's all related to how high you've dialed the flame, the strength of your draw, and the distance of the heat source. And the final ingredient is the thermal quality of the soapstone itself which quickly becomes very integral.
And then before I stop lighting, I begin to draw the flame upward, reducing the temp at the stone but still drawing the heat down until you take it away and shut it off - again keeping any unburned fuel from the air path. This also gives you a real sense of how you can "play" your instrument to find the right warmth to get the terpy hits or build the deeper hits - and each subsequent hit will be easier and faster as your stone maintains and increases in warmth.
In my experience, using a Colibri level fuel and never having the flame itself introduced into the path, I get a completely clean hit.
Last thing on the technique - the Fire/Wind/Earth symbols in our logo are about this balance of the heat, the draw and the stone...with
the stone being the "magic" ingredient.
Also to continue my little torch taste epic, One of the Magic Stoners I facetimed with, while beta-testing the torch approach, has an Alchemy and a full range of torches from his work as a chef. Which of course is a common technique for finishing any number of recipes at the finest restaurants, enjoyed by connoisseurs almost as discerning as FC members.