Here is part of an interview with a guy who runs a lab and regularly test BHO.
" When you’re testing for concentrates there are several different consistencies – like wax, budder, shatter, etc. Does one consistency generally test “dirtier” than the others?
Based on what we've seen, I would say shatters are consistently dirtier then budders. Then again, I've worked for a couple companies that do some forms of shatters that never have any contamination in it, so it's kind of a hard question. There are so many variables that contribute to “dirty” BHO.
What's the best or worst brand of butane to make BHO?
A lot of people think N-Butane is great to run with because the closed-loop system is a cleaner way to run stuff. In the test results I've seen, it’s not necessarily the cleanest way to run it. It looks like there's much more of a saturation happening in a closed-loop system with N-Butane. I don't think the people have their timing right there. I think the product is sitting in the gas and the liquid a lot longer and the molecular structure of N-Butane is a chain, just like the tail end of the THC cannabinoid structure, so there's a bonding going on there.
So running with just N-Butane wouldn't be as good as running with a combination of Propane, ISO Butane and N-Butane?
In the 1,000 samples that I've seen so far, I would say N-Butane probably has shown significantly dirtier results. Usually, runs using Newport, Vector or a Power x5 canned gas test at an average of 1-3 PPM – and that’s from somebody who I would consider to be an extraction artist. I would say generally that canned gases are cleaner."
http://www.hightimes.com/read/herbal-synergy-lab-testing-cannabis-and-concentrates
Also, the whole boiling water in an empty pot analogy is completely irrelevant. We are not just simply trying to boil off butane in an empty pot. We are trying to extract butane that has saturated another substance without burning or changing said substance.
And by industry standard, I am talking about the standard of the legitimate cannabis industry(and even large parts of the illegitimate cannabis industry) that has generated billions of dollars already. It would be silly to assume that your chemist friend has more knowledge and expertise on the subject than the people directly involved in this highly competitive and progressive industry. It would also be assuming that out of all these people who are capable of what the industry has achieved this far, no one has stopped and researched their industry or product. If anyone has a religious type of faith to what it is they believe, it is you.
