So imagine this completely hypothetical situation...

I've done a STB on an Australian Acacia tree bark using Na2CO3 and pulled with "100% liquid hydrocarbons" (ie. no residue), and my resulting product faintly smells of my non-polar solvent even after a few days.

My questions are this:

Are there many natural oils present in the bark of Acacias?
And if so, would the non-polar solvent be miscible with these oils and be prevented from properly evaporating?

Also I do know some chemistry so breaking it down into bite-sized pieces won't be necessary.

Cheers,
Your friendly neighbourhood Igel.

Well..... I just had a look at what I've got and a cheeky little poke and hiding under some brown basified gunk was crystal! Extraction = success, albeit a poor quality product. I know now the importance of having absolutely NO BROWN GUNK when evaporating down.

there can be oil like alkaloids in the bark that do not crystallize under conventional methods for extraction
they are typically not what you are looking for