I purge BHO at 115-120F at down to -29.5" Hg in a thin film until the bubbling slows to a crawl.
The short explanation:
The 115-120F is to ensure the oil is in liquid state for the butane to easily escape the matrix.
The down to -29.5" Hg means I don’t ever pull past this point. I don’t leave the pump running, which would take the vacuum down to -29.9", which I believe is unnecessary as the 115-120F @ -29.5" Hg is deep enough to remove any moisture, and pulling a deep vacuum on and on possibly disturbs the matrix leading to waxing up. I go for shatter, and consider other products unfortunate ‘accidents.’ But feel free to cook up whatever waxes, budders, honeycombs, crumbles you want, just don’t expect me to buy into them as premium grade product.
This process will get you to below the residual butane solvent standards as quickly/efficiently as possible, further purging is unnecessary imo, and I’ve presented a long and thorough case for my opinion in a single thread previously.
“At what ppm can you taste butane?”