Post subject basically says it all. Been extracting dmt for around 5 years and I've never done the recommended evaporation of half of the NPS prior to freeze precipitating. Wondering how greatly is my yield affected by this ie is there a bunch of dmt left in the NPS that won't crash out ?

I guess another question I have while I'm at it is in regards to just totally evaporating the NPS rather then freezing altogether. When doing this is the final product the same as from freezing or is it more oily waxy etc?

I don't think it affects the total yield that much, only the yield from each pull. And when each pull yields less, you'll still get most of the goodies out, it just takes more pulls.

Pretty sure it's stated somewhere here that dmt has a hard time crashing out of solutions that aren't all that saturated . I've always took that to mean that once alot crashes out and the NPS becomes less saturated it stops to crash out although the NPS still contains dmt. There fore you can evaporate some to get the concentration higher again and more will then crash out .

Is this logic correct

Edit
from the faq

Interesting, I'd love to hear other people's findings.

On my first and only spice extraction I've done so far I just put the dish straight into the freezer without pre-evap and got around 1g of yellowy crystals from around 40g of MHRB, which is supposed to be quite a good yield according to the people I've discussed it with.

I used cyb's hybrid atb salt tek. Soon I shall do a second go at it, this time with the max ion tek and ACRB.

Following this thread. Be well.

Pre-evap is necessary to make the NPS solution saturated to the point when DMT starts to crash out.

Freezing NPS solution makes most, but not all, DMT to crash out. A small amount of DMT always remains in the NPS even a low temperatures. So the the smaller the NPS volume the better your yield. To check it you may you evaporate the NPS decanted from freeze-precipitated DMT. There always be some small amount of DMT remaining.

So, why then we freeze-precipitate DMT instead of evapping the NPS completely? This is because NPS also dissolves some impurities that do not crash out even at low temperatures. It allows to obtain more pure product. If the NPS volume is small DMT losses will be negligible.

How to know when to stop reducing the NPS solution? When your NPS gets cloudy close to its boiling point you may stop reducing it.

It is also advisable to use NPS with high DMT solubility at boiling temp and low solubility at low temp e.g. heptane.

To obtain pure crystalline DMT several re-crystallizations may be required.

Usually I evap combined NPS pulls completely and obtain honey-colored thick oil. Then I extract it 5-7 times with small amounts of Heptane (10-20ml), combine these pulls and reduce the volume until Heptane becomes milky-white, keep it at RT for an hour, put it in a fridge (wrapped with a film) for another hour and then in a freezer for 8-12 hours.

Another reason for freeze-precip is the lye contained within the non-polar solvent (or rather within the water mixed with the solvent). With evaporation it stays within the result, but when freeze-precipitating, much of it stays in the solution and do not crash out.