That's true for most solvents. Naphtha is also believed to be potentially carcinogenic, so I don't think you're any safer using naphtha. D-limonene, now that's safer for sure.

Good news, some nice white crystals have formed in the first two jars, looks like a gram or so, however there is no more spice in the remaining two jars, i believe that i did something wrong, what might be the reason? Im still very happy to pull my first spice. Is carbonate wash neccessary or can the spice just be dried and smoked? I'll post pics when it's ready. Thanks everyone who helped me!

Nice! You may need to evaporate 50%-75% of the volume of your non-polar solvent frm the 2nd and 3rd pull and repeat the freeze precipitation.

As far as the carbonate wash, it is going to be useless with the already precipitated crystals. What one can do now is to recrystallise the already precipitated spice. This will get rid of the residual impurities.

thanks! and yeah i didnt use the whole 1 kg of mhrb, only 230g, so dont think that the yield is 0.1% Ill try to evam the remaining pulls!

IS it ok that some crystals are on the bottom of the jar and some are floating in the cold hexane? Is it possible that there is lye there? Is lye soluble in hexane? Im not sure whether to recrystalize it or not.

naptha is kind of a general term for solvents. ive seen several different products that contain naptha. You want a solvent that contains mainly aliphatic hydrocarbons. I have used white spirit successfully, but it has to say naptha on the bottle, not turpinitine. The white spirit in the UK i used turpintine substitute (b&q). It says on the bottle naptha, its mostly aliphatic hydrocarbons but there is still a fair amount of aromatic hydrocarbons. its heavy naptha and takes forever to evaporate.

With the white spirit it doesnt turn yellow and i got fairly clean spice. When freeze precipitating after pouring the solvent off leaving the container of crystals upside down for 12 hours helps get rid of any remaining solvent drain off and avoids redisolving the crystals.

Lye in your solvent will be obvious. It will stick to crystals leaving a very dark colour on them. Infact you will notice lye if you get it into your solvent when extracting. It sinks to the bottom of the jar and sticks to the glass. I had that a few times and simply poured my solvent back into the root bark/lye solution jar, cleaned my precipitation container out and re-extracted the solvent making sure only to get solvent.

As for the crystals floating in the solvent, sometimes that happens. if your doing more pulls simply pour to solvent back into your solution. if not evaporate the solvent.

I used White spirit from B&Q for my first extraction and since it is "hydrotreated heavy" it becomes very hard to freeze precip and takes forever to evaporate. I now use ronsonol lighter fluid for all my extractions, as it is light naphtha and freeze precipitation works like a charm. Just thought i'd let you know white spirit will work ok, but ronsonol works a million times better. Peace

My first pull was done with white spirit and it freeze precipitated fine for me without evaporating any.

My later pulls i used ronsonol lighter fluid and didnt notice a difference except i could evaporate it much easier.

I was however using less solvent, for 25 grams of rootbark i was using maube 15ml of solvent.