Just done a quick google and this one comes up top, I'm fairly sure it's the same one though it was a while ago I read it, but a quick scan looks familiar.
Inhalable, noncombustible cannabis products are playing a central role in the expansion of the medical and recreational use of cannabis. In particular, the practice of “dabbing” with butane hash oil has emerged with great popularity in states that ...
www.ncbi.nlm.nih.gov
It's actually a surprisingly readable paper and pretty interesting generally, though a bit older than I recalled.
That seemed like a lot of trouble to go through (though I am a lazy b'stard, it must be said!). I found putting a small bed of vaping cotton/rayon at the bottom of the bowl, then heating the hash on a pin/knife until it's hot enough to crumble finely, or if too oily or otherwise won't crumble well with modest heat, then breaking it up with finger nails, or scraping with a knife blade when cold and hard, whatever, as long as it's nice and small particles. Then I just gentle hoover it up with the straw method, I tamp it
ever so slightly and only with a finger tip, not a hard tamper, so it's still very loose, but not spilling out the bowl.
Then heat the 'pest up to near combustion levels (for weed, that is) and hack away at it. Usually cleans almost everything out of it with a few tokes, rarely even need to reheat it. AVH always comes out as dry and turns to dust between fingers. Little or nothing left in it.
Also, less is more sometimes, putting too much in blocks the airflow and makes it harder to extract the volatiles.
The three factors I hit on, were how fine it's broken up, how loosely it's packed in the bowl, and how much heat is applied.
Done this with 'pollen' types (leb etc), and some indian charas (that worked
really well, crumbles very fine with little heating), the only one I had a little trouble with was some top grade cream from Goa, which was so oily and solid it wouldn't crumble so had to be pulled into small bits which is a little tedious and in the end didn't vape as well despite being stronger. The softer hashes would crumble finer if left to cool and harden after an initial crumble.