I'll be using Norman's STB extraction later next week for my first extraction - lots of excitement and anticipation.

I've read through half a dozen or so teks, and browsed the forums here and elsewhere a bit...from what I can see there is a general consensus that slowly evapping produces the largest crystals (could be wrong).

Why is freeze precipitation used at all? Because it's faster, or produces a cleaner product, or another reason?

Freeze precipitation drops the product out of solution very quickly. It is then possible to remove most of the solvent without evaporating (and losing it to the atmosphere). Once the crystals precipitate, they can be redissolved in a minimum of solvent and recrystallized slowly. Conclusion: freeze precip is faster and wastes less solvent than a slow evap. Hope that helps!

I agree with Umantis but I would also like to add that, yes evap does make big crystals, but your solvent MUST be clean or free of plant oils/fats and other organic artifacts. If you solvent is not free of those items your going to have cystals and allot of gooey waxy residue.

Umantis hit the nail right on the head. Freeze precipitation is great because you waste less solvent, you get the spice as quickly as possible, you usually get a much cleaner batch especially if you've been careful and you don't have loads of solvent evaporating inside your home or apartment which isn't the nicest or safest thing. After I have my freezer precipitated spice harvested I redissolve and remove any impurities and leave the solution in a shot glass at room temp with a paper towel and a rubber band over the top. 20-30 milliliters usually evaporates in this fashion of the course of a few days, don't disturb it and the end result should be a lovely big crystal like the one here:

https://www.dmt-nexus.me/forum/d...aspx?g=posts&t=32335

also when you freeze precip you leave behind a lot of the oils and gunk that are still in the naptha, whereas with evapping you get everything that was in the solvent.

Awesome thanks for the information everyone - that clears it up!

I'll be doing my extraction later this week, will post results!