High torch over. DMT does not alter chemically when it "burns", at least not at the temps we do it, and no concept of wanting to slow burn it light pot.
Don't use a torch, that is an no no.
If you've smoked DMT before you would know this.
As for DMT not chemically altering when it burns, this is false.
Burning is a chemical process in its self, burning leaves makes CO2, burning any kind of fuel makes gases and other components.
Similarly with DMT, when it burns it forms byproducts.
Although not all of the byproducts are know, skatole (3-methylindole) is believed to be one of them.
Skatole is known to be toxic, so torching DMT like you say to, should not be done.
Vaporizing on the other hand does not chemically alter DMT, but physically make it into vapor that one can inhale.
DMT isn't to particularly stable and will oxidize under high temperatures, but not much if vaporized and not torched.
If you gently vaporize DMT with a lighter then you will get full effects, you wont have as much of a nasty taste, you will not burn causing a chemical change in the substance.
Please do not give advice that you are not certain about testtime.
EDIT:
You are talking crystals melting into oil. Are you telling me the DMT molecule has gone through any type of transition in that moment?
When I say temp makes no difference, I am using pot as a baseline (where temp has a huge effect), so maybe I'm offbase. I mean like how THC has a bunch of different terpenes as well, and they all interact at differnt temps, and the THCV (oh, running from poor memory) decarboxylates (no, I will NOT google it), and therefor turn into THC at a certain temp. And THC itself vaporises at about 360, but around 500 or so it decomposes into something else that you may not want, so it is temperature sensitive. THC also oxidises on it's own, just sitting there. Quickly.
DMT oxidises as well, but it seems to last forever (in my feeble history), and seems to be very stable.
DMT is not the most stable substance, I don't know were or how THC comes into play here but THC is a much more stable compound than DMT.
Like Anc said if you have a vial of DMT and you subject it to heat, it will form oxides of DMT, through the day more and more.
DMT N oxide is an is a liquid at 23C, DMT freebase is a solid at 23C.
The DMT doesn't just simply melt, that would be apparent once it is cooled back to room temperature.
"(no, I will NOT google it)"
Seems like you need to do more of that.