A friend of mine obtained about 400grams of Acacia colei bark, apparently it is quite high in DMT and not many other alkaloids. He did an acid/base extraction, all went swimmingly, It is now in a freezer -35 crystals allready precipricating.

how long should he leave it in the freezer at the least?

Edit:

decieded to evap instead but was left with an oily residue i didnt defat so i think thats what the problem was. care to shed some light?