It’s done by grinding lower grad pot into a fine powder and then dripping alcohol through it to extract the essential oils. This is usually done in a sealed low temperature distillation setup.
The danger comes when people try to rush the process and increase the heat to the ignition level of the alcohol.
Don’t ask how I know this.
How do you know this? :)
Thanks for your insight, which I’m sure is due to your being well-read. I would have guessed the cause was careless use of open flame heating and vapor ignition. Same problem as storing flammable liquids near the furnace.
Why not just use butane, ice and a series of filters?
The real problem isn’t alcohol, it’s Butane. You can make hash oil 10x faster using Butane than alcohol. (don’t ask how I know this).
I image the problem occurs because of inadequate ventilation and/or when somebody decides to use a stove directly and not using a hot water bath like a careful person would.
When butane fumes build up, it can easily go off with a flick of a light switch.
Industrial production of hash oil uses a vacuum pot operating at normal temperature. Instead of raising the temperature and creating that danger, you lower the atmosphere and force the boil-off at lower temperatures. This also has the added safety of being able to pump the fumes out of the workshop.
OK, long time ago, and I mean long time, we played hash oil.
Way we did it, a lower pot on a low burn had the finely ground pot in ethanol (we made do with Everclear, close enough). From there, a reflex condenser so we didn’t just boil off the ethanol, top pot collects and drains back.
Continue, SUPERVISED for about 12 hrs. Pour the extract into a glass baking dish, allow that to evaporate to a solid film. Scrape it off with a razor blade, voila Hash oil! Never had to worry about weighing or packaging, this was totally for use of us and friends.
I can also give better tips than most on growing pot, yeah I did all that in the 70s. Got a job driving trucks, got to pee in a bottle every time I turn around, gave it up a long time ago.
And no, it was not addictively hard to quit. If cigarettes were as easy to lay down, I’d be an ex-smoker.
Don’t sweat it Lurker, statute of limitations ran out a long time ago.