My question is,
Some teks such as lazymans tek call for an evaporation, others such as Nomans for a freeze precipitation.

What is the difference with the results?
is one more effective?

Evaporation will yield the entire product but will not let you reuse solvent unless you are distilling it. Freeze precip might retain some product in the solvent though the amount would be negligible. I think evaporation would be more prone to trapping solvent in the crystal lattice than freeze precip but that is just an intuition of mine. Nothing wrong with either, but freeze precip will save you money by allowing you to reuse solvent and it will keep the smell down. If you have to do the whole extraction indoors or if you live in apartments you don't want to be evaporating your solvent.

i think i may be trying an evaportation soon because i feel as if my freezer is not getting cold enough,

is a home freezer on the coldest setting cold enough?

when doing an evap is there a big chance of ending up with dmt oxide?
sorry i dont know the correct terminology, but that yellow goey stuff ive heard about. haha

If you get the product really hot and expose it to the air for a long time you can turn a lot of it into n-oxide but I wouldn't be to worried. You could freeze it out in a wide mouth mason jar. Just get a styrofoam cooler and fill it halfway with dried ice than stick your mason jar in there. Use a wide mouth so you can get your hand in there to scrape.

sounds good SWIM will be getting soem dry ice tomarow !

I don't know it it is a common practice, but during my extractions I always freeze precip, reuse the solvent a few times, and then when that does not yeild any more spice I take the used solvent and put it in my evap pan with the xylene. I dont know if this has positive results, but it eases my mind that im not wasting any of that delicious spice.

Hi all & thank you for all your input making this site an excellent source of information for SWIMs first attempt.

I don't have a freezer and was intending to use the evaporation method from the lazyman tek. SWIM is a bit worried he will not get the desired end result required, could someone who has tried both methods please let him know if evaporation will give him his desired spice.

Cheers and thanks for reading

i would say freeze precip to get as clean of spice as you can, Freezing will most of the time result in small clustered crystals around whatever container it may be in, and evaporating will get you nice solid full crystals but will obv take a little longer than frezzing.

Hey, sooo evap/freeze is the question.... As already mentioned the evaporation smells terrible (depending on solvent, yeah, but i think all solvens smell like crazy chemist lab... ), nevertheless an initial evaporation of solvent, lets say to less then half the volume makes it possible to "freeze precip" even at room temperature or in the fridge... SWIM constraints the solvent completley under cold airflow, so that crystals form. Then he adds a littel tiny bit of hot solvent again, and is able to percitipate even at roomtemperature. The ammount of noxid formation is tiny, and can be sucked off with a pasteur piette. But as I m sure that not everyboody has full acess to well equipped laboratories the best thing to do is to evap lots of the solvent on a heater under an open window (DO NOT USE AND FIRE AROUND)... and afterwards freeze precip for couple of days. SIWM uses HPLC grade solvents, thus has no contamination of endproduct, but as the usual folks use commercial available solvent please dont forget to check your solvent for impurities.

So generally speaking its up to you, how you harvest your product depending on how fast you want to visit hyperspace.
An excess in solvent gives purer product, but the freeze precip takes longer. The excess of solvent using complete evaporation makes not much sense, as impurities will remain in your chrystalls. To yield purer product you would have to resolve your product in a little bit of solvent and let it precipitate at RT, fridge or freezer... best thing to to is all of them startiing at RT

I look at it like this:

Evap will get you everything, including some plant oils that were picked up by the solvent. These have no where to go and get stuck in the spice when evaped, causing yellow goop at room temp (guess how I know...)

Freeze precip will let most of the crystals crash out, but only some of the impurities will have a chance to fall out. They fall out at different rates, as I'm sure you've seen in the re-x threads (brown layer, x-tal layer, solvent, etc...). So while you'll leave a bit of spice in there, you'll leave more of the impurities in the solvent, and end up with a much cleaner product (guess how I know )

A clean product will stay crystallized at temperatures warmer than comfortable (guess how I know )

This has been very enlightening. I had tried to recover a goop before by adding more solvent, but it didn't seem to... dissolve. I never thought to reheat the whole mess to reintegrate it and try precipitation again!

Thank you

Depends on the solvent used but in case of naphtha: Why not do both?

You can evaporate approx. half of the solvent (40% original volume or until it's milky/cloudy) and then freeze precipitate.

The point of freeze precip. is that DMT is practically insoluble in naphtha at 0 C (32 F) and even less at below freezing temperatures. The the other stuff such as oils will however stay dissolved. Most freezers runs at -18 C (0 F).

The freeze precipitation is therefore also a purification technique.

I would not evaporate the solvent as an alternative to freeze precipitation.

When you freeze precipitate, some very small amount of solvent and a very very small amount of impurities may/will get trapped in your snow globe, but the rest is poured off. If you were to evaporate instead, perhaps most of the solvent will evaporate away but the impurities will then be concentrated into your spice.

Please please please, if you can freeze precipitate, then do that. As blue.magic mentioned you can evap down to ensure that freeze precipitation will be successful.

You only get one set of lungs. Be careful with them. I say this as someone who has been foolish and did NOT freeze precipitate once upon a time. Do what you will, you might be fortunate. Then again, you might not. If it seems like I'm trying to scare you, I'm not. But I hope you will appreciate the risks and act appropriately.