I have some plant matter soup stored (not sure if acacia or mhrb, but probably acacia because it is redder and doesnt have as strong a scent as mhrb/lye soup would have). Its been sitting around for almost a year now. When I last tried to extract acacia I did a STB instead of an acid base extraction. (All I got was a reddish liquid that didn't crystallize.) So this liquid is basified, but it hasn't been defatted (and I've never done an A/B extraction). I would like to try to recover what I can from this.. so what should I do to defat an already basified solution? Reduce it, then add white vinegar, defat and re-basify, then pull with naphtha? Or what?

Don't reduce liquid in the basic stage of the extraction. De-fat (which you actually don't need to do) is done in the acid stage. Freeze precipation removes a fair amount of oils from the final result whatever.

I suppose if you were intent on working A/B on your material you could add acid to your basic solution to bring the pH back down and then reduce. This all sounds a a bit if a messy way to work to me though. Maybe you could extract as is, then acidify the result, basify and re-extract.

It is to be noted that Acacia confusa has a mixed alkaloid profile, it contains both NMT and DMT as the main alkaloids. NMT does not readily crystallize and forms as an oil. The oil will solidify with a bit of scraping about and leaving it for a few days. You can separate NMT/DMT as NMT drops out of naphtha at room temperature given some time. You can then freeze precipate to get mostly DMT.

Don't throw away the NMT, it is active, just quite different to DMT.

In my experience Acacia confusa doesn't need a defat but you would be better using an A/B extraction for the material over STB.