Given that DMT-fumarate melts at 152°c wouldn't that mean that contact with the bottom and sides of the pot destroy the molecules as they are of a higher temperature?

Would a soft boil be considered safe?

Just because something reaches melting point doesn't mean it is degrading.

You can safely boil DMT salts even with strong boiling without any loss.

Yes! Thank you endlessness. I do wonder though, if the water was left to evaporate completely and the crystals were just sitting on a hot dry stove whether it would start to burn... Where would you stop boiling off the water and let it to air dry instead?

Think aya brews. A brew can be reduced down pretty far. With a small enough pot 50ml I about as far as I have been able to reduce before it is too thin a layer of water to continue.
Keep in mind you must be very careful with heat & stir almost constantly when the solution starts to get thick or it will burn.

Once it gets down to ~50ml you can pour (or scrape depending on how saturated & thick) your solution into a Pyrex dish & set it in front of a heater vent or a small fan for a day or two.
If you have a/c to keep your house cool, you can use a space heater to heat the air blowing from th fan onto your tray to speed things up a bit.

It does burn, I accidentaly left the pot on medium low aiming for 50ml as concombres suggested but I forgot and came back to sludge that was burning and smelt like vaporized dmt.

I washed the sludge in water quick smart and after some fizzing I observed tiny harmine-like crystals crashing out which was unexpected from that black/brown sludge. I would say I lost a decent amount because of this.

Hard to know if/how much you lost unless you had a control group and did an extraction afterwards (or at least bioassay with both) to compare.

Either way better avoid forgetting anything in the fire haha.. But yes, aya is often reduced till very thick consistency and is very potent. Just to be prudent, you could reduce to low fire one it's small amount of liquid left, so that the last part is reduced more slowly/safely.

You're confusing melting/boiling with thermal decomposition. One way you can control the heating is with a double boiler. I.E. water boils at 100C, so if you used a double boiler you won't exceed 100C.

Problems may occur from uneven heating. When the kettle bottom becomes much hotter than the water. Area of the kettle may get extra hot and flash boil the water into vapor. These can be observed and bubble rising to the surface.

You can avoid uneven heating by using boiling stones, or stirring.

Edit:

DMT, has a very high boiling point. 340-350C. DMT acetate has a significantly higher boiling point. The temperature of the water (100C) would act as a condenser in the event that much dmt was being flash boiled. Especially in the event that water was being improperly heated, and that the majority of your vapors exited as gas bubbles from the bottom.

To boil off water more effectively you need to stir the solution so that it heats evenly, so vapor could rise off the entire surface area of the water rather than intermitent bubbles.